Copy multiple fields in a form to the same form for revisions

OK, so i would create a child table called Revision History.  The fields would be [Changed by] (a user field)  and then a field called [Field changed] and then fields for old value and new value.

Then i would set up an ACTION to write into those child table when the record is modified and a certain a certain changes.  i sounds like you just have a few fields to log.

The you an show the embedded table of the audit logs in a Tab on your form.