You wish to obtain a $200,000 mortgage that you will use to purchase an office building and are offered a rate of 6% per year compounded monthly for 25 years; in other words, use the rate per month compounded monthly of 6% divided by 12 = 0.5%. Monthly payments start one month from now.
Determine your monthly payment that you will need to budget for.
Five years from now (immediately after you have made your 60th payment) you can refinance the remaining 20 years of the mortgage at 0.4% per month compounded monthly. Assuming you decide to refinance, what will be your new monthly payment?