Part/Serial Rename and Weighted Average

Let’s say a part serial is renamed to another part number. This will result in one PARTREN- transaction with the old part number and a PARTREN+ transaction with the new part number. Later, a revaluation event causes the PARTREN+ transaction to be revaluated, because of the WA logic. Now there is a difference in the cost between the two transactions, since the PARTREN- transaction was not revaluated. Will that not leave the account used on the M191 posting with a balance that will be hard to explain?