The use of money interest rate for underpayments is higher than that applying to overpayments. In 2015 SoundExchange sued Muzak for underpayments of royalties to artists and rights holders. After the roll out, there were continued complaints about underpayments, over-payments, and non-payments. In two years, he recalculated 3,237 sorts and discovered 1290 underpayments. For instance, the GAO estimated that underpayments amounted to ~$160 million USD in 2006. The underpayments involved over 1000 employers in Wales. AIT sincerely regrets the underpayments of its valued and hard-working staff.