Hello Barb,
You might want to review
this document to see whether it helps clarify how you might set up BankRec, Payables and Ledger.
I know that the discount rate changes by different credit card types within a single brand, but the automatic calculation works fine for EFT and PAD (pre-Authorized Debit). Even within a credit card brand, the fixed percentage may be adequate if the discrepancies are not material.