Seconday Cost element Category Uses and Importance.

Hi ,

Can any one explain me the seconday cost element uses and importance in cost accounting ?

Especially for the Cost element categories

21-Internal setellment.

42-Assesment.

43.Internal Activity allocation.

32-Order/Project result analysis.

when to use which cost element Category and examples.

I understand in the Cost sheet for the Overhead Calculation we use Seconday CE category 41.

But in the Allocation structure at the time of giving the Cost elements, i will get confused to assign the CE's.

This will be the great help.