It does add difficulty, because you now have to plan ahead; you have to put yourself in a position where you can move to the rear/flank of the boss in the time it takes for your GCD to come back up, and plus it'll catch you out if you use jump before the 4th.

The luck is the same as every other positional you have. You'll miss your Chaos Thrusts in Ravana Ex like you'll miss your 4ths there.