Possibility of Custom SLA for AR Receipt write-off and refund

Summary:

Is it possible to write custom SLA for AR receipt write-off and refund? If yes, how to achieve the same.

We have 20 entities with their respective transaction types and all of their receipts are created with just one receipt method/bank. Whenever a receipt is created and applied to AR Invoice, IC line is generated due to difference in entity (segment 1) between cash and receivable, which is fine. But client wants write-off and refund to have same segment 1 (entity) and segment 3 (division) of that of Receivables class. I can achieve write-off accounting as desired by creating 20 different write-offs, but with increasing entities, maintenance would increase. So, to avoid that, we want to use custom SLA to