Reversed MO posts cost difference to a rounding account

A manufacturing order is reversed and a cost difference is posted to a rounding account.   This occurs when the inventory valuation method is FIFO Perpetual and there are items remaining in an earlier FIFO layer at a higher cost.  When the MO receipt is reversed and the manufactured items come out of inventory, the earlier FIFO layer is used creating a variance.  This is working as designed.  But in this case, there is a difference in costs coming out vs what went in.  While not really rounding in a sense that we would usually think of, does the Variance – Material account for the FG make sense?  Or does the Variance – Material account from the components make more sense?  What about if there are multiple components with different accounts – some percentage calculation per component?  And then what if there are fractions left – does that go to Rounding? I suspect that was designed to just go into the Rounding account as it could be considered a difference between what went in and what came out as a ‘rounding’ ( although we might not agree with that in a strict sense ).