Ten years ago, your parents put 20% down on a 30 year mortgage for a $350,000 home at 8%. Today they could refinance the mortgage for $1500. They plan to stay in the home for 5 more years and were offered a 15 year adjustable rate mortgage with a starting rate of 5%. Interest rates are expected to stay at 5% for the first three years before decreasing to 4% for years 4 and 5. Should they refinance?