you should not file an amended return until the taxpayer's original return is fully processed. The IRS computers should catch the math errors and adjust the return accordingly. Then when you file the amended return you start with the return as corrected by the IRS. There may be no need to file an amended return if the IRS catches all the errors and if any other changes you would make will not change their tax liability/refund
you would not be able to e-file the amended return if you do overrides.
