Incorrect gross pay and allowances figures for one staff member in STP

Have just noticed that the gross amounts and allowances for one staff member submitted in STP are grossly incorrect since July!  All my export files have been successfully submitted to the ATO so didn't think to check each individual entry plus PAYG amounts are correct.  So, 1. are the export files from payroll premier incorrect and 2. how can gross pay and allowances be adjusted and advised to the ATO?  Any help would be much appreciated.