Load VT , start with VT (or C:VT)
Click on one of the attdef's , you get the main dialog
Click on setup (bottom right) and change difference to 5 , click on ok to return to main dialog
Finaly click on Renum and select all attdefs , enter, done...
VT uses grread in a constant loop so exit with escape, cancel or spacebar that will get you in quick menu and you can escape / Quit / cancel from there.
Not all buttons will work because some are company specific like revision but for now it should get you what you need.
VT.LSP