Recharge Time Entry

We are trying to correct an issue with some timecards that were posted incorrectly to employees.  Since these are for recharge hours they don't effect payroll but we need to remove them from the F0618 file.  We thought we could upload the incorrect time as a negative and that would create the net effect of zero when reports were generated.  My questions is, can we use the action F in the Recharge Time by Employee to manually upload all the incorrect records?  This action code is disallowed by default, is there a way to allow this action?