Well, we do quite a mix, but the main problem is with our truck jobs, which are massive and complex (kinda redundant, I guess).
For those, we never report quantity by operation; we just backflush everything at job start and hope for the best and yell later.
Where it gets tricky (or it used to) is when we are trying to run out a part (deja vu) and we accidentally backflushed one we don’t have, so we have to return it.
Or I think more likely the problem was when we used to backflush later, at literal job completion, but we just wanted to issue (i.e. with the Issue Material screen) a run-out part right now so we could use up all the quantity and inactivate it and be done with it. Then somehow, despite unchecking backflush (maybe too late), it still backflushed a second quantity later.
Yeah I have wondered (1) how it remembers that you issued a part (not backflushed), and (2) why it remembers. Who cares if it was issued or backflushed? Quantity of it got to the job.