This type of allocation is not well-known - using the Financial Report Writer to build a financial report that can create journal entries. This is a great way to reorganize departments, moving balances from one department to another, even going back in time to whatever month in the past required. I had one client back in the early 2000's in World build out basically what Advanced Variable Numerator Allocations can do now, but the beauty of using FRW is the lack of requiring proof or the lack of having to do any special voiding. These FRW-built journal entries simply create JE's directly into the F0911 with a batch to post. Any mistakes can just be a simple void and re-run of the month to build again.
Creating FRW-designed reports are quite simple, but there are specific steps to be aware of when building for journal entry purposes. This Knowledge Document, (KB330178) E1: 83: Overview of Journal Entries Creation using Financial Report Writer does a great job of showing these details.
If you want to tackle this with a Denovo expert, let us know!