Just wondering if you have cross checked your system's payment calculation with an HP or with EXCEL. I know that with the parameters that have been set in our ARTA system [which is to be replaced later this month] I cannot obtain a true "mortgage style" amortized payment; in our case, the derived P&I is somewhat higher, which results in a slighly more rapid amortization.
I have created my own EXCEL spreadsheet amortization, and usually the final balance is shown at $0, or is within a very few cents if there is any difference due to rounding.
"When you believe He's all you need,that will be your defining moment." [from "Defining Moment" Newsong, Sheltering Tree CD]