Right now Tokyo is 8 hours behind PST, so if it's noon here, it's 4AM there. Usually the updates start at 10am PST, so they are starting work at 2AM in Tokyo (if that's where the servers are located). Lets play with some numbers and see who gets left out where.

EST 3AM - PST Midnight - Tokyo 4pm 
lasting through 
EST 11AM - PST 8AM     - Tokyo Midnight

Obviously, that would kill an entire night for JP players, so that's probably not the best idea of when to start an update.

EST Midnight - PST 9pm - Tokyo 1pm 
lasting through 
EST 8am      - PST 5am - Tokyo 9pm

Again, not the best time because it cuts of Tokyo the same way it cuts of EST time zones now, and kills PST off at 9pm.

EST Noon - PST 9am - Tokyo 1am 
lasting through 
EST 8pm  - PST 5pm - Tokyo 9am

Amazing what 1 hour can do, I don't know many people that play past midnight, and doing it this way cuts an hour off the EST (and PST) wait time after work.

EST 8pm - PST 5pm - Tokyo 9am 
lasting through 
EST 4am - PST 1am - Tokyo 5pm

Normal workday hours in Tokyo, but kills NA times, I'm really glad they do not do it during these times.

Truely, I've never sat to figure these times out before. In fact, the time they DO do updates is actually a pretty good time. They could make it a little fairer for everyone if they started it about 2 hours earlier, but it's better than some of the times I've posted up there that "*****" a lot more people at one time. I'm usually not one to complain, but I did start with the update on the 13th, I'll know to keep my mouth shut from now on. ;)