Hi
MF70 works fine if you set "1:immediately in update program" for backflush and calculate actual cost in confirmation processes. I guess right now these field are filled with "2:later in background job" because you said job is doing fine. please change these field s if you want to work with MF70 in blow configuration path:
Production-->Repetitive Manufacturing-->Backflushing-->Separate Backflushing-->Define confirmation processes.
Regards