Sage 50 Canada

Hello, I am wondering if there is a way to add a 3% fee to invoices that would automatically be calculated on an amount, similar to HST. I considered setting it up as a sales tax of sorts, however, from what I understand, you cannot have two tax codes…

When interest is added on the customer statement, that line is being overprinted with the "% daily compounded (% yr.) interest on balances overdue Interest more than 30 days" message. When I go to Reports and Forms, I don't see this as a text or field…