Ann wants to buy an office building which costs $2,000,000. She obtains a 30 year fully amortizing fixed rate mortgage with 80% LTV, an annual interest rate of 4%, with monthly compounding and monthly payments.

The mortgage has a 2% prepayment penalty if the borrower prepays in the first 5 years. Suppose Ann makes the required monthly payment for 3 years and prepays after her final monthly payment at the end of 3 years. What is the annual IRR on Anns mortgage?

the answer is 4.60%

But when I do the CFs on my calculator its wrong. Can you please help:

CFo= -1,600,000

CF1= 7638.64

FO1= 35

CF2= 1,549,857.84

F02= 12 (because it's last year)

Please let me know if my inputs are incorrect.