Office of the Comptroller of the Currency Chief Counsel Julie Williams said one large mortgage servicer under its supervision uses more than 250 different foreclosure affidavit forms, according to testimony Thursday before the House of Representatives Committee on the Judiciary. Six of the largest mortgage servicers in the U.S. admitted employees signed affidavits without properly reviewing documents, sparking investigations from regulators and 50 state attorneys general. Congress heard yet another round of testimony from regulators and industry heads on the recent robo-signing issue, totaling four hearings in both the Senate and the House. Williams pointed out that Fannie Mae and Freddie Mac, who outsource servicing rights to thousands of companies including these largest servicers, require them to use a network of law firms and other real estate service providers, creating "a panoply of documents used in their mortgage foreclosure process." It's one symptom of a servicing system overwhelmed with delinquencies. According to Lender Processing Services data, 2.1 million loans are currently in the foreclosure inventory with another 2.2 million loans more than 90-days delinquent but not yet in the process. She did not disclose the name of the servicer that uses so many different forms, but she did say even these operational challenges do not absolve the banks from their responsibilities. The banks should still maintain "appropriate staff, quality controls, and an effective audit process in place to ensure that documents are accurate and the foreclosure process is conducted in compliance with applicable state and local laws," Williams said. Write to Jon Prior.