How is the best way to handle AP-Payment Terms (E1 9.2) when you have prorated discounts and prorate

How is the best way to handle or set up AP-Payment Terms (E1 9.2) when you have the following situations:

1. Financial discounts but they are calculated based on a fixed % plus on a variable % (Total Discount Rate = Fixed % + Variable%). Beyond that, you must calculate a prorated discount rate which depends on the advanced payment day. In this case, you don't have already predefined the payment term. Only negotiated when the supplier requires cash for its operation and requests from you the payment in advance (payment terms),
2. Fine (maximum 2% or less) + Interest, both are always calculated at the same time. Each one is