It can also be seen that a negative amortization schedule would give the same balance owing of $18,979.73 (close enough to 18,980). The approximate difference between $145,803 – $126,824 = $18,979. In other words, $15,440 now is worth $18,980 thirty six months in the future (FV) if it is appreciating at .575% per month . Stated differently, $15,440 now is worth $18,980 three years in the future(FV) if it is growing at an effective interest rate of 7.1224415.

Note that most interest rates are not normally quoted to more than two decimal places because of the difficulty in getting agreement in the PV/FV calculations as the equations exponent is very sensitive to the number of decimal places used!

Another way of looking at the numbers is as follows. If one deposits $476.04 per month, every month for 36 months, into an account paying interest at 0.575% per month then after 36 months $18,980 will have accumulated.