I would like to see if I'm doing this correctly.

A borrower can get a mortgage for $400,000 over 30 years with the following terms: a. Initial interest rate =4% b. Index =1 year Treasuries c. Payments adjusted annually d. Margin =2% e. Negative amortization = yes f. Based on forward rates the index is forecasted as follows: Beginning of year BOY2=3%,BOY3=5%,BOY4=6%,BOY5=8% Compute the payments, loan balances, and the cost of borrowing over a 5 -year period