Fixed Payment Terms & February

We have configured fixed payment terms for each day of the month to allo our pre-authorized payment customers the flexibility to pay on the date they prefer. We've created our payment terms to ensure that if the billing takes place after the fixed due date, and the bill assumes a due date of the fixed date + 1 month.

Example: Portion 17 = ZF26 (Fixed Date of the 26th of the month)

It will bill Jan 27, and the bill will automatically withdrawn on Feb 26th

We have now come across an issue with February. Portion 17 bills on the 24th of the month - because February is a short month and the payment term does not add a month when the due date is prior to the bill date. So, when it bills on the 24th, the invoice assumes a due date of February 26th, and our customer will no whave two bill amounts coming out of their account on the 26th of February (the Jan 27 bill and Feb 24 bill).

We can't just always add 1 month to the due date because we have customers billed in portion 2 on the 3rd of the month who can have payment terms of ZF26 and that should be the same month as the bill, not the following month.

Does anyone have any experience in configuring fixed payment terms for February?

Thanks ...