Handling Payment Credits in an Accounting System

[RWX]

I'm working on an accounting and class registration system for a school and would like some advice on handling payment credits. I have an Invoices table, a Classes table, and a Join table connecting the two. The Join file stores all of the data regarding the student's enrollment in a class. A Payments table is used to track student payments as students may pay for a class over time in installments.

My question concerns how to handle student withdrawals. When a student withdraws from a class, he/she may choose to receive a refund (based on the amount paid to date, classes taken, a refund fee, etc) or a class credit. If the student chooses class credit, he/she receives a credit to be used towards future class(es). A class credit may be applied towards a single class or multiple classes (ie: split).

My first inclination was to simply include this information in the Join table. When the student withdraws, I set a flag indicating that the student has withdrawn and store a credit amount. Here's where it gets a little complicated...

The enrollment record that has now been flagged as withdrawn becomes a credit. A Credit Splits table joins the enrollment Join table with a second instance of the Join table. If John Smith withdraws from Class 101 and receives a credit of $200, when he signs up for Class 102, he may apply that $200 from the earlier Join record to the new one via the Credit Splits table. I hope that makes sense. :-)

I often feel that if something is too complicated to explain, there's probably a reason. And that's how I feel about this Class Credit situation. Would I be better off creating an entirely new table to store Class Credits, one that would be Joined to the enrollment record or is storing the credit information within the enrollment record the way to go?

Any thoughts on this would be greatly appreciated!

-Rob

[comment]

Can't say I understand your structure, so just a thought:

You say "A Payments table is used to track student payments as students may pay for a class over time in installments."

Wouldn't a credit be just a negative payment?