I want to use a time stamp to notify if a modification is made after a approval checkbox is checked

I have a situation where our legal department must review all the fields that others have filled out.  Once they have reviewed and approved the information in the form they select a check box which has an associated date stamp (time/date field).  However, there will be instances where other users will need to edit some of the fields after the approval.  I set up a rule for both the form and notifications that trigger if the last modification date time is later than the approval date stamp.  Works fine.

But there is a problem.  In the rule when the modification is after the approval it will remove the check in the checkbox indicating that the lawyer must re-approve once they have looked at what ever was modified in the record.  BUT because the rule says uncheck when the modification date is newer than the approval date (and it remains that way) when they click on the approval box again it will not take it.

Any wonderful ideas out there?