In the text below, you will find descriptions about how lead times are calculated and used within IFS Cloud. To reach the section you are interested in, please use the following bookmarks:
Lead times in inventory part
Lead times in supplier for
purchase part
Lead times
in supply chain parameters
Lead time on
site
Total purchase lead time
To fetch correct ship via into customer order and purchase order
Ship via code on customer order
Supplier ship via
transit on customer order line
Ship via and supplier ship via transit on customer order line created from source
line
Ship via on purchase order
Lead times in customer order
Lead times in shipment order
The total lead time of a purchase part is the time from when the part is ordered until it is available in inventory, i.e., the primary supplier's manufacturing and external transport lead times, transport lead times plus the internal transport lead time and the internal inspection lead time. You can calculate the total lead time of a purchased part in the Calculate Purchase Lead Time dialog box. The result of the calculation is presented in the Acquisition tab of the Inventory Part Page when using the Update option.
For an external service order there will be more lead times associated such as External Service Lead Time and External Transport Lead Time. The External Transport Lead Time will be used since the repair part is sent to the supplier via a customer order process.
Note: Safety lead time will not be considered as a component in Purchase Lead Time.
For manufactured parts, the lead time is the collective lead time for manufacturing the part from its components. Manufacturing lead times can be found in the Acquisition tab as well as in the Manufacturing tab. These lead times can be calculated using the lead time calculations found in Manufacturing Standard/Calculation or in the Routing page.
The expected lead time is the time, in days, that it takes to receive the parts into inventory assuming that not all component parts are in inventory. Therefore, the value in this field includes acquisition lead time as well as manufacturing lead time. For example, let's say that you manufacture a part consisting of several components and one of the components is not in inventory and must be ordered. In this example, the manufacturing lead time of the part is incorrect because it assumes that all parts are available from inventory. Thus, you should use the Expected Lead Time field to help ensure that a part can be delivered in time, even when not all components are in stock.
You can manually enter the lead time in the Expected Lead Time field. The expected lead time can also be calculated using the lead time calculations Calculate Purchase Lead Time found in IFS/Purchasing, and Cumulative Lead Time Calculation, Lead Time Calculation, and Change Cumulative Lead Time found in IFS/Manufacturing Standards.
The default value for the Expected Lead Time field is 0 (zero). If no expected lead time is entered in the inventory part record, the expected lead time is the same as the purchase or the manufacturing lead time.
Primary supplier's safety lead time which is defined in the supply chain matrix will be updated in the Safety Lead Time field. You can update the safety lead time of a part using the Modify Safety Lead Time dialog box. The result of the calculation is presented in the Planning tab of the Inventory Part page. You can manually update this value.
External Service Lead time is only applicable for Supplier for Purchase Part records with External Serviced Allowed parts and suppliers combinations. This is defined in the Supplier For Purchase Part / External Services tab. External Service Lead Time it tightly connected with the External Service Type field.
In the supplier for purchase part record, you can specify a supplier manufacturing lead time and an internal inspection lead time per combination of supplier and purchase part. Both these parameters are parts of the total lead time when goods are delivered from one node in a supply chain to another. However, it is important to note that these two lead times are not the only parameters included in the total lead time. Other lead time parameters involved in the total lead time are external transport lead time, internal transport lead time, and picking lead time.
In the supply chain parameter and the supply chain matrix pages, you can specify external transport lead time and, for some relations, internal transport lead time. Both these parameters are parts of the total lead time when goods are delivered from one node in a supply chain to another. However, it is important to note that these two lead times are not the only parameters included in the total lead time. Other lead time parameters involved in the total lead time are supplier manufacturing lead time, internal inspection lead time, and picking lead time.
Picking Lead Time: The average time it takes for a supply site to pick the goods ordered on a customer order for delivery to a customer. The picking lead time is measured in distribution calendar days, which includes only work days. This parameter is one part of the total lead time when goods are delivered from one node in a supply chain to another. Other lead time parameters involved in the total lead time are supplier manufacturing lead time, internal inspection lead time, external transport lead time, and internal transport lead time.
The total lead time of a purchase part is the time from when the part is ordered until it is available in inventory. The total purchase lead time is normally calculated in the Calculate Purchase Lead Time assistant by using the following four elements:
When you specify the Update option when calculating the total purchase lead time, the result is presented in the inventory part record.
If the calculate purchase lead time function is not used, the default value will be set to 0 (zero). However, it is also possible to manually enter a value in the inventory part record.
The total purchase lead time is used for calculating dates when entering purchase requisitions or purchase orders.
The data shown in the supply chain parameter pages and in the supply chain matrix pages are exactly the same. Therefore, only the supply chain parameter page will be referred to in the description that follows.
One of the key fields in the supply chain parameter pages is the Ship Via field. The ship via code describes how the goods will be transported from one node in a supply chain to another. When a customer or purchase order is entered, the ship via code is fetched from the supply chain parameters. Along with the ship via code, the external transport lead time and the internal transport lead time are also fetched. You can enter a ship via code in several places in IFS Cloud, not only in the supply chain parameter pages but also on customer agreements, on supplier agreements, or on the customer or supplier record. It is important that the correct ship via code is fetched into the customer or purchase order since the ship via code determines the external transport lead time and the internal transport lead time. However, internal transport lead time is not saved on the customer order, it is only used in the total lead time calculations. On a purchase order, neither internal transport lead time nor external transport lead time is saved.
In the table below, the fetching of the ship via code into the customer order header and the customer order line is described. The Order Default check box on the customer order line will remain selected only when the ship-via code and the external transport lead time are identical for the customer order header and the customer order line and there is no deliver-from supplier defined on the order header. If there is a deliver-from supplier on the order header and if the customer order line is created with supply code Internal Purchase Direct or Purchase Direct and the line supplier is same as that of the header deliver-from supplier, the Order Default option is enabled for that line. In the description below, the upper table and lower table refer to the different parts in the supply chain parameter pages, where the lower table defines exceptions for certain supply chain part groups.
Header or line? | Which supply code? | Ship via code fetched from... |
Header | N/A | First, from the agreement (general information). Second, from the default ship via code specified in the supply chain parameters, upper table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. Third, from the customer record. If deliver-from supplier exist, first from the default ship-via code specified in the supply chain parameters, upper table for Deliver from supplier to External customer. Secondly, from the agreement (general information). Thirdly, from the deliver-from supplier. |
Line | <> Internal Purchase Direct or Purchase Order Direct | First, from the agreement (part specific information). Second, from the default ship via code specified in the supply chain parameters, lower table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. Third: 1. Inherited from the header. 2. If the order is for a package component, inherited from the package's order line. 3. If the address is different from the header address, from the default ship via code specified in the supply chain parameters, upper table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. Fourth, only if address is different from header address, from the customer record. |
Line | Internal Purchase Direct | First, from the default ship via code from the
supply chain parameters, lower table. If the customer is external, from
site-to-customer. If the customer is internal, from site-to-site. Second, from the default ship via code specified in the supply chain parameters, upper table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. Third, from the supplier record. If deliver-from supplier and line supplier are same, then first from the default ship-via code specified in the supply chain parameters, lower table. Secondly, from the customer order header. |
Line | Purchase Order Direct | First, from the default ship via code from the
supply chain parameters, lower table. If the customer is external, from
supplier-to-customer. If the customer is internal, from supplier-to-site. Second, from the default ship via code specified in the supply chain parameters, upper table. If the customer is external, from supplier-to-customer. If the customer is internal, from supplier-to-site. Third, from the supplier record. If deliver-from supplier and line supplier are the same, then first from the default ship-via code specified in the supply chain parameters, lower table. Secondly, from the customer order header. |
Note: When ship via code is retrieved from the agreement, if the Consider by Quotation/Order Header option is enabled on corresponding customer agreement, ship via code will be retrieved to non-agreement price source sales quotation lines/customer order lines as well.
One exception from the above is when the order line has a single occurrence address. Then the following should apply:
Note that an update of the ship via code and/or external transport lead time is necessary if the prerequisites are changed. It is only if a customer order line has its Order Default option enabled that a change in the customer order header will affect the customer order line. The following changes have to be considered:
If the deliver-from supplier exists on the customer order header and order line supply code is either Internal Purchase Direct or Purchase Order Direct, then the Order Default option does not get selected.
In the table below, the fetching of the supplier ship via transit into customer order line is described. The Order Default option is not affected by this field. In the description below, the upper table and lower table refer to the different parts in the supply chain parameter pages, where the lower table defines exceptions for certain supply chain part groups.
Header or line? | Which supply code? | Supplier ship via transit fetched from... |
Line | Internal Purchase Transit or Purchase Order Transit | First, the default ship via code specified in
the supply chain parameters, lower table. If the supplier is external,
from supplier-to-site. If the supplier is internal, from site-to-site. Second, the default ship via code specified in the supply chain parameters, upper table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Third, from the supplier record. Fourth, if no record exists for the default delivery address on the Supplier/Address/Purchase Address Info tab, the ship via for the first delivery address will be fetched. If no delivery address exists at all, the field will be set to NULL.. |
Note that an update of supplier ship via transit is necessary if the prerequisites are changed. The following changes have to be considered:
In the table, below the fetching of the ship via code, supplier ship via transit, and external transport lead time into the customer order line created from the source lines is described. The Order Default option on the customer order line will remain selected only when the ship via code and the external transport lead time are identical for the customer order header and the customer order line. In the description below, the upper table and lower table refer to the different parts in the supply chain parameter pages, where the lower table defines exceptions for certain supply chain part groups. Note that external transport lead time either represents the delivery from the order-taking site to the customer, or the delivery from supplier/supply site directly to customer. Consequently, when the correct external transport lead time is fetched from the supply chain parameter pages, the ship via code is used, not supplier ship via transit.
Which supply code? | Ship via fetched from? | Supplier ship via transit fetched from? | Delivery lead time fetched from... |
Inventory Order | Source line | N/A | First, from the supply chain parameters, lower
table. If the customer is external, from site-to-customer. If the customer
is internal, from site-to-site. Second, from the supply chain parameters, upper table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. |
Internal Purchase Transit or Purchase Order Transit | Copied from originating customer order line | Source line | First, from the supply chain parameters, lower
table. If the customer is external, from site-to-customer. If the customer
is internal, from site-to-site. Second, from the supply chain parameters, upper table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. |
Internal Purchase Direct | Source line | N/A | First, from the supply chain parameters, lower
table. If the customer is external, from site-to-customer. If the customer
is internal, from site-to-site. Second, from the supply chain parameters, upper table. If the customer is external, from site-to-customer. If the customer is internal, from site-to-site. |
Purchase Order Direct | Source line | N/A | First, from the supply chain parameters, lower
table. If the customer is external, from supplier-to-customer. If the
customer is internal, from supplier-to-site. Second, from the supply chain parameters, upper table. If the customer is external, from supplier-to-customer. If the customer is internal, from supplier-to-site. |
Note that If the deliver-from supplier and line supplier are the same, the ship-via code is fetched from the customer order header.
In the table below, the fetching of the ship via code into purchase order header and purchase order line is described. The Order Default check box on the customer order line will remain selected only when the ship via code and the delivery lead time are identical for the customer order header and the customer order line. In the description below, the upper table and lower table refer to the different parts in the supply chain parameter pages, where the lower table defines exceptions for certain supply chain part groups.
Header or line? | Demand site is? | Ship via fetched from? |
Header | N/A | First, from the default ship via code specified
in the supply chain parameters, upper table. If the supplier is external,
from supplier-to-site. If the supplier is internal, from site-to-site. Second, from the supplier record. |
Manual line | Same as header | First, from the supplier agreement. Second, from the default ship via code specified in the supply chain parameters, lower table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Third, inherited from the header. |
Manual line | Different from header | First, from the supplier agreement. Second, from the default ship via code specified in the supply chain parameters, lower table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Third, from the default ship via specified in the supply chain parameters, upper table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Fourth, inherited from the header. |
Line from requisition | Same as header | First, if the requisition originates from a customer
order, the ship via code is inherited from the customer order line:
for transit delivery field Supplier Ship Via Transit, for direct delivery
field Ship Via. Second, from the supplier agreement. Third, from the default ship via code specified in the supply chain parameters, lower table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Fourth, inherited from the header. |
Line from requisition | Different from header | First, if the requisition originates from a customer
order. the ship via code is inherited from the customer order line:
for transit delivery field Supplier Ship Via Transit, for direct delivery
field Ship Via. Second, from the supplier agreement. Third, from the default ship via code specified in the supply chain parameters, lower table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Fourth, from the default ship via code specified in the supply chain parameters, upper table. If the supplier is external, from supplier-to-site. If the supplier is internal, from site-to-site. Fifth, inherited from the header. |
Line from customer order | N/A | If the purchase order line originates from a customer order, the ship via code is inherited from the customer order line: for transit delivery field Supplier Ship Via Transit, for direct delivery field Ship Via. |
Note that an update of the ship via code is necessary if the prerequisites are changed. It is only if a purchase order line has its Order Default option enabled that a change in the purchase order header will affect the purchase order line. The following changes must be considered:
When a customer order is entered, several different lead time parameters are involved. These parameters provide for a correct calculation of different dates as well as a correct availability analysis.
The supply code set on the customer order line determines which parameters above should be included when calculating the total lead time since the supply code tells which source should supply the ordered quantity. The source can be another site (i.e., internal supplier), external supplier, in-house manufacturing, or own inventory. These different sources all have different total lead times. Consequently, it is important what supply code a customer order line carries. The supply code on a customer order line can be set automatically, via user-defined sourcing rules, or manually. The following supply codes are relevant when discussing total lead time: Inventory Order, Shop Order, DOP Order, Internal Purchase Transit, Internal Purchase Direct, Purchase Order Transit, and Purchase Order Direct. For further details, please study the example and the tables below.
Example: Supply code Internal Purchase Transit and the sales part is an inventory part at order taking site (B) as well as supply site (A):
The planned delivery date is the date we (B) plan to deliver the goods at the customers delivery address (C). Since we do not have the part in stock, we must order the part from another site (A) within our company group. Since we want to have control of the final shipment to the customer, we will first receive the goods from the supply site to our site, and then deliver it to the end customer. Site A is an internal site and, therefore, the supply code on the customer order line will be set to Internal Purchase Transit. In order to find out if it is possible to deliver to the customer on his wanted delivery date, a date calculation must be performed. Initially, we will assume that we can deliver at the customer's wanted delivery date, i.e., planned delivery date on the customer order line will be set to wanted delivery date. A backwards calculation is performed, as shown below: planned delivery date If the inventory part at the supply site has the Availability option enabled for the inventory part, an availability check will be performed at the supply site on the supply site due date. If the availability is less than the ordered quantity, or if the supply site due date is an earlier date than today's date, it will not be possible to deliver the customer order line in time. |
In the tables below, you will find all lead time parameters used when calculating the total lead time for the different supply codes. You also will find the dates that are set on a customer order line when the sourcing is completed. And you will find a specification telling if it must be a work day or not, and in that case what calendar to use. In the tables below, you will see that the different scenarios are dependent on whether the sales part is an inventory part or a non-inventory part. This is relevant for the order-taking site as well as the supply site. Also note that in all total lead time calculations as well as date definitions, routes are considered. Routes are considered for both the order-taking site and the supply site.
Inventory Order:
Customer order line date? | Minus which lead time parameter? | Does it have to be a workday/workdays? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date | Yes | Distribution | |
Picking lead time | Yes | Distribution | |
Planned due date | Yes | Distribution |
If the inventory part has the Availability option enabled, an availability analysis is performed.
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
Shop Order and DOP Order:
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date | Yes | Distribution | |
Picking lead time | Yes | Distribution | |
Planned due date | Yes | Distribution | |
Expected lead time | Yes | Manufacturing | |
Start date | Yes | Manufacturing |
Note, that even if the expected lead time is zero (0), the start date on the shop order or DOP order will be set to the day before planned due date.
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
Purchase Order Transit (in which the sales part is an inventory part at an order-taking site) and Internal Purchase Transit (in which the sales part is an inventory part at an order-taking site, but a non-inventory part at the supply site):
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date | Yes | Distribution | |
Picking lead time | Yes | Distribution | |
Planned due date | Yes | Distribution | |
Internal inspection lead time | Yes | Distribution | |
Internal transport lead time | Yes | Distribution | |
External transport lead time | Yes** | External Transport | |
Transport lead time | Yes** | External Transport | |
Supplier manufacturing lead time | Yes*** | Supplier |
Note: It is not recommended to work as in the Internal Purchase Transit case described above if the order taking site and supply site belong to the same legal unit, since the inventory value will be wrong; the goods will have an inventory value in one of the sites but not in the other.
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
*** If no supplier calendar is defined, a 365 day calendar will be used.
Purchase Order Transit (in which the sales part is a non-inventory part at the order-taking site) and Internal Purchase Transit (in which the sales part is a non-inventory part at the order-taking site as well as at the supply site):
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date and Planned due date | Yes | Distribution | |
Internal inspection lead time | Yes | Distribution | |
Internal transport lead time | Yes | Distribution | |
External transport lead time | Yes** | External Transport | |
Transport lead time | Yes** | External Transport | |
Supplier manufacturing lead time | Yes*** | Supplier |
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
*** If no supplier calendar is defined, a 365 day calendar will be used.
Internal Purchase Transit (in which the sales part is an inventory part at the order-taking site as well as at the supply site):
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date | Yes | Distribution | |
Picking lead time | Yes | Distribution | |
Planned due date | Yes | Distribution | |
Internal inspection lead time | Yes | Distribution | |
Internal transport lead time | Yes | Distribution | |
External transport lead time | Yes** | External Transport | |
Picking lead time | Yes | Distribution | |
Supply site due date | Yes | Distribution |
If the inventory part at the supply site has the Availability check box selected, an availability analysis is performed on appropriate site.
* If orders are automatically created, the planned delivery date will fall on a work day. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
Internal Purchase Transit (in which the sales part is a non-inventory part at the order-taking site, but an inventory part at the supply site):
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date and Planned due date | Yes | Distribution | |
Internal inspection lead time | Yes | Distribution | |
Internal transport lead time | Yes | Distribution | |
External transport lead time | Yes** | External Transport | |
Picking lead time | Yes | Distribution | |
Supply site due date | Yes | Distribution |
Note, it is not recommended to work as in the Internal Purchase Transit case described above if the order taking site and supply site belong to the same legal unit, since the inventory value will be wrong; the goods will have an inventory value in one of the sites but not in the other.
If the inventory part at supply site has the Availability option selected, an availability analysis is performed on appropriate site.
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
Purchase Order Direct and Internal Purchase Direct (in which the sales part at the supply site is a non-inventory part):
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date and Planned due date | Yes | Distribution | |
Supplier manufacturing lead time | Yes*** | Supplier |
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
*** If no supplier calendar is defined, a 365 day calendar will be used.
Purchase Order Direct and Internal Purchase Direct (in which the sales part at the supply site is an inventory part):
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date and Planned due date | Yes | Distribution | |
Picking lead time | Yes | Distribution | |
Supply site due date | Yes | Distribution |
If the inventory part at the supply site has the Availability check box selected, an availability analysis is performed on appropriate site.
Customer order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned delivery date | No* | Customer | |
External transport lead time | Yes** | External Transport | |
Planned ship date and Planned due date | Yes | Distribution | |
Supplier manufacturing lead time | Yes*** | Supplier |
* If orders are automatically created, the planned delivery date will fall on a workday. However, it is possible to manually enter a planned delivery date as a non-working day. If no customer calendar is defined, a 365 day calendar will be used.
** If no external transport calendar is defined, a 365 day calendar will be used.
Shipment order uses four lead times. These lead times have the same definition as when used in other orders or processes. Respective field description describes in what order default values are found. The lead times are:
When a shipment order line is created, the Wanted Receipt Date is the
fixed date (taken from the shipment order). The other dates are calculated
using the lead times, routes and calendars with the Wanted Receipt Date as
the starting point. Calculated dates will land on a work day according to
the corresponding calendar.
When changing a date on the line, that
date will be considered the new fixed date and the remaining dates will be
recalculated with that as a starting point. All dates are editable and have
to be a working day in the corresponding calendar.
Shipment order line date? | Minus which lead time parameter? | Does it have to be a work day/work days? | Which calendar to use? |
Planned receipt date | Yes | Receiver Site/RW Distribution | |
Internal transport lead time | Yes | Receiver Site/RW Distribution | |
Planned arrival date | Yes | Receiver Site/RW Distribution | |
Transport lead time | Yes* | External Transport | |
Planned delivery date | Yes* | External Transport | |
External transport lead time | Yes* | External Transport | |
Planned ship date | Yes | Sender Site/RW Distribution | |
Picking lead time | Yes | Sender Site/RW Distribution | |
Planned due date | Yes | Sender Site/RW Distribution |
* If no external transport calendar is defined, a 365 day calendar will be used.