Component Backflushing Issue with Repetitive Manufacturing

Dear PP Expert,

I'm facing a problem for component backflushing using repetitive manufacturing, enclosed is the case of client:

• Repetitive Manufacturing with Planned Order only, no Production Order used;
• With MES (Non-SAP ME) integration for backflushing interface:
  • Key component backflushing information will be transferred from MES to SAP ECC, and the key components are maintained as alternative ITEM in the BOM with 100% 'Usage prob.'.
  • On the other hand, other normal components will be backflushed against the BOM or Planned Order BOM (depend on whether input the planned order number during backflushing process).

            That means the component backflush for the GR will be two parts, one is real consumption from MES for key components and other consumption from SAP BOM master for non-key components.

Because user cannot change the 'Usage prob.' after the BOM is created, since it is maintained by a PLM system through the interface instead of manual, if manual change will impact the interface based on existing design. Based on existing situation, now the problem is:

• if 'Usage prob.' is maintained 100% for each alternative component / item in the BOM, let's say 3 alternative parts maintained within the same alternative group, the planning during MRP phase and the backflushing based on standard REM MFG will consume EVERY component, it will be triple consumption than the real consumption which is wrong (user accept triple planning to keep the stock, but not allow the over consumption than real consumption).

I'd like to double confirm with you, in the case above, is there any other standard SAP function to resolve this issue? At least as I know, the possible way is only finding some BAPI & BADI to resolve this issue w/o SAP standard solution in REP MFG. But the consequent issue if we call BAPI or BADI is every time the planning run during MRP phase, actually the reservation is already booked in table RESB, we have to remove the redundant reservation in RESB table for other alternative components, that is reason we want to avoid to use BADI.

Thanks!