... Disagreements over real estate values are nothing new, but agents, builders and sellers say current market conditions, plus recent changes in federal rules that effectively encourage banks to use in-house or affiliated appraisal management companies, are magnifying the problem.

In a recent survey of members, the Massachusetts Association of Realtors found that more than half of agents said sales had been hampered by appraisals that came in low. Polls by the National Association of Realtors also have documented widespread frustration over faulty valuations, and the association ranks them among the major causes of contract cancellations. ...