One-quarter of homes for sale in Austin, Texas, (25.8 percent) have lower estimated monthly housing payments than they would have if they had been for sale a year ago, according to a new report from Redfin. That’s a higher share than any other major U.S. metro area and more than triple the nationwide share of 7.1 percent. Seattle is close behind, at 23.6 percent, followed by San Francisco (18.8 percent),...