Admin/Early Payment Discount and Late Payment Fees

Late Payment Fees and Early Payment Discount fees are applied when a payment is applied against an invoice and the invoice outstanding amount is reduced to zero. 

This means for example if a payment is initiated before the due date, but clears after the due date, a late payment fee would still be applied.

At this time there is no functionality to arbitrarily apply the fee once the invoice becomes overdue, though it is being discussed with the developers with no current ETA.