A lower rate will not only result in a lower payment, it will amortize the loan quicker. A $250,000 mortgage at 4.5% for 30 years will have a $1,266.71 principal and interest payment. At 4%, the same loan will have $1,193.54 payment saving $73.18 a month and the unpaid balance would be $1,776 lower at the end of five years. Mortgage lenders tend to price their mortgages based on the credit score of the...