Average mortgage interest rates increased significantly during the week ended September 23. As a result, the Mortgage Bankers Association (MBA) said the volume of mortgage applications gave back most of its prior week gains when it had increased for the first time in six weeks. The Market Composite Index, a measure of mortgage loan application volume, decreased 3.7 percent on a seasonally adjusted basis from one week earlier and was 4 percent lower on an unadjusted basis. The Refinance Index dropped back by 11 percent week-over-week and was 84 percent lower than the same week one year ago....