We need a separate field for the amortization period since it is actually quite common to have (for example) a ten year loan, amortized over 20 years. Meaning, the payment amount is based on paying the loan over 20 years, but the maturity date is after ten years, so there will be a large payment due at maturity for the balance of the loan. We would like to have a way to input this into the system as we currently need to "cheat" in order to get things to work. One drives the payment calculation and the other drives the maturity. This said, we would like to be able to calculate that outstanding amount due when the amo period is larger than the term. On fixed interest loans, you would just deduct the principal payments paid during the term from the initial loan amount.
