2 layer pro rata of tuition

Hi there

I charge students termly and let parents re-register each term online rather than enrol them myself and then invoice.

I know I can prorata my sessions and I do, but at the start of a new term I switch that feature off so that returning students are charged for a full term even if they miss the first week or 2 of the new term and only register on week 2 or 3. If I set prorata on at this point in the term I would be loosing money from these returning students.

The issue arrises when new students trialing for the first time over the same period are charged for the full term rather than just from the week they enrol.

So what would be amazing is if there were 2 layers to the prorata option; 1 that targets old / returning students and 1 that targets new students signing up after a trial.

Thanks so much.