I still don't understand why the compound master data is needed in the planning level.
So lets say in the above example we have a planning level as PERPRODCUST with PERIOD, PRODUCT, CUSTOMER and PRODUCT-CUSTOMER
Now lets say we don't have P4 in the compound master data table. Then we cannot load P4 sales data.
We also will not be able to see any key figure data related to P4 at PERPRODCUST planning level. So the planners using the system should be very aware of the products or customers that do not exist in the compound master data table.
So coming back to my question, what is the reason to have the compound master data part of the planning level?