SE seem to be keen on maintenance from 6am to 10am GMT (1am to 5am EST) and a lot of the planned maintenances fall into that window (+1 hour to those times when on summer time like now). In Japan that's 2pm to 6pm (they don't use summer time).
I have no idea exactly how they picked that window (combination of when staff/support contracts are active as well as to impact on least number of players), but whenever they schedule a maintenance it's always going to cause problems for someone.
Realistically they can't do a different maintenance time for each region as a lot of the planned maintenance are for all worlds, it doesn't make sense to have to do 3 separate maintenances when they could the whole lot at once and that also assumes players are on the server of their region. With North America also having timezones with a difference of over 5 hours, it's just not possible to make everyone happy.
