Default Question about roms and 4.2 and 4.4

I just recently rooted, flashed recovery, made it brickproof with nvflash and put my first rom(cromi x) on my tf300t.(woohoo) Im on 4.2 jelly bean and was wondering (1)can I flash 4.4 roms straight from 4.2 or do I have to offical update then do everything over again? (2) If I flash a 4.4 rom and did not like go back by a simple flash of a 4.2 rom?