Price bands

Have a price break selection for each customer, based on their payment history - if a customer pays immediately, within terms, they would be say, A1. A bad payer who takes 90 to pay would be say, C3. We would like to offer a customer who pays well a better pricing structure than a customer with a bad/slow payment history. As I understand it at the moment, all prices have to be inflated to C3 status and then discount applied to achieve A1 status. In most businesses, A1 customers are more the norm and therefore likely to be the higher number, so this should be the default, not C3.