Indeed, if the BIOS is 100% compatible this can work. I have an MSI MS-6168 that will accept both retail AMI and Packard Bell OEM Award BIOS.
Note that you can't do this with normal flash tools on the board itself. Uniflash will let you flash it, but it needs to work on your board and Asus does strange stuff with its BIOS flash circuitry so it usually does not. You'll need an EEPROM flasher or another board that Uniflash does like to hotflash.
Advantage to both methods : you can use them for recovery if things don't work as desired