Personally I don't make dual bios the same until After I know the master is good and stable and not corrupted or buggy. Having that second bios untouched is cheap insurance should anything happen.
If there's an issue with the new bios, and it fails for some reason or another, bios will revert to the last known good bios boot. Or it's supposed to anyways after a set number of attempts (default is 3). Also, if you have a user profile set to load, it'll boot to that bios even if you change it and save it (F10), until you save the new bios as the user profile.