PROBLEM: Right now, payment methods (credit card / ACH) can only be set two ways — account-wide, or per customer profile. Neither works for shops that charge a credit card processing fee and let customers choose bank payment to avoid it. Here's the gap: a customer tells us on the phone or by email that they're paying by bank transfer, so we remove the credit card fee from their invoice before sending it. But because payment methods aren't tied to the invoice, the credit card option is still sitting right there on the payment link. The customer clicks it, pays by card, and we've already removed the fee — so we either eat the cost or have to go back and ask for it after the fact. Locking the customer's profile to ACH-only doesn't solve it either, because the same customer doesn't always pay the same way order to order. One month they're bank, the next they want to pay by card. A profile-level lock has to be manually flipped back and forth, and it's easy to forget. REQUEST: Add a payment method setting on the individual invoice — card only, ACH only, or both — that overrides the account and customer defaults for that one invoice. That way, when a customer commits to a payment method for a specific order, we can lock that invoice to match, remove or keep the credit card fee accordingly, and know the customer can't click into a payment method we didn't intend for that invoice. This would help any shop that surcharges credit card transactions, or that simply wants to honor a customer's stated payment method per order instead of guessing at the account or customer level.
