A primary cost elements is for CO the equivalent as accounts in FI with the same codification that is detailed in the page GL Accounts codification tables.
In PF2
The codification of a primary cost element is:
6 when it is a cost & 7 a revenue
9 digits : it can depend on the use of the cost element
In WP2
The codification of a primary cost element is:
98 : primary cost element
6 digits that can depend on the use of the cost element
There are 2 types of secondary cost elements:
Cost elements to transfer costs between cost centers, orders & WBS
Cost elements to transfer costs from the cost centers to COPA (in PF2 we speak about "Reporting cost elements")
In PF2
The codification of a cost element to transfer costs between cost objects is: