COBOL Loan Calculation Fix / Dashboard Modification

I maintain a legacy financial framework written entirely in COBOL and have traced a fault to the loan module: the routine that calculates each payment's amount is producing the wrong numbers. The mis-calculation... (Budget: $30 - $250 USD, Jobs: COBOL, Cold Fusion, Debugging, Delphi, Dispatch Software, F#, Financial Modeling, J2EE, Silverlight, Software Development)