Commercial banks and savings institutions continued to backpedal away from the business of servicing residential mortgages for other investors during the third quarter, according to a new Inside Mortgage Trends analysis of bank call reports. Banks and thrifts serviced a total of $4.139 trillion of home mortgages for other investors at the end of September, most of them pooled in mortgage-backed securities. That was down 1.2 percent from June and off ... [Includes one data chart]