Three of the big four accounting firms have written to the Financial Accounting Standards Board, recommending that the agency change Generally Accepted Accounting Principles to allow mortgage servicers to report mortgage servicing rights at fair market value. The accounting firms, Ernst & Young, PricewaterhouseCoopers and Deloitte & Touche, said the change would negate the need for special hedge accounting, but it could also cause volatility in earnings for those lenders that do not hedge