Credit Card Convenience Fee - Percentage + Flat Fee Feature

Under this feature "Credit Card Convenience Fee Percentage Feature" Under Financial---> Online Payments you can specify the percentage you want to charge to the customer who is paying by credit card. The Stripe gateway that Populi integrates with has a convenience fee schedule of Percentage + Flat Fee. We only want to charge our customer the payment which the Stripe will take from us or deduct so we want to have an option of specifying the convenience fee as a combination of % + Flat Fee. This will also help us in eliminating needless complexing when accounting in our Quick Books accounting software.