(Internal) Convenience fee for customers who pay with a credit card

We have opened up credit cards as an option for customers who owe a total of less than $10,000 on their open invoices. For all credit card transactions, we are going to pass through the processing fee charged by our credit card processor, which is 2.9%. This is called out to customers when they click through the credit card option in the Upflow billing portal and is not refundable. If they want to pay via credit card, they must pay this fee.