Its not so much about it being a jp or na group. Its that parties formed and had 2 hours to do all the pre'reqs and reach the hard mode. Then, servers shut down. When the servers come back up, the parties who planned it out and worked together to get pre'reqs prob wont be there. Most ppl dont have 5 hours to wait around. Even the jp players will prob have other things to do. So a lot of groups will have to help others clear the pre-reqs to get to hard mode which could take another 2 hours extra easy.

There will be less parties -trying- for the hard win than if there was never a maintenence.
so people who guessed low numbers will be at a disadvantage while those who guessed high numbers will be at an advantage.

Essentially the final result won't -really- be how long it took to kill garuda, it will be how long it took to kill garuda, with a 5 hour maintenence in the middle. So anyone who made their prediction based on a continuous party trying to kill garuda will have been screwed. And thus the entire thing turns into a random lottery.