Hi Szymon and Surya,
I have investigated both COPA Assessment (CCA -> COPA) and Top Down Distribution. Both cannot handle cumulative allocation. Cumulative allocation would be very complex and performance intensive i.e.:
1. Calculate cumulative allocation;
2. Calculate delta between YTD current closing period and YTD last period;
3. Post the delta by profitability segments.
These has to be done for each profitability segment. Perhaps, the performance constraint can be resolved using Hana but current logic of allocation does not support cumulation.
My recommendation is to perform this allocation in BI (e.g. BW). This will require scripting but I think it's relatively easier to handle. You can even write a logic on what to do when there is no reference data for allocation.
However, if you still want to do this in ECC, you will need to consider work around solutions. For example, you can consider having the YTD costs and drivers posted in the closing period via special accounts (used for allocation purpose only, allocation reference data can be summarized in CE2 table). The allocation results in PA can be reversed in the current closing period via special postings with custom record types. Then you can manipulate the allocations and results accordingly.
That said, I am still not particularly convinced of the gravity of the requirement. Allocation, by it's nature, implies inaccuracy and we should really weigh the costs and benefits of such an undertaking. Considering that the calculation process itself is already very complex, you will need to develop reports and processes to validate the results.
Kind regards,
Teck Liang