This activity is used to select the base for cost/revenue element. Any code
part other than code parts assigned to functions can be selected as a base for
cost/revenue element. It is not possible to change the selected code part as
long as connections between the code part value and follow-up elements exist
in the Cost/Revenue Element per Code Part Value page.
As a result of this activity, cost/revenue elements can be connected to code part values of the selected code part in the Cost/Revenue Element per Code Part Value page.