Two hours forward is still a norm time. 5am wouldn't be out of that norm, either. Two hours back (Midnight) would be shakey. You aren't thinking of weekend playtime (later), summer (no school), and people who just play later in a few of the neighboring time zones. California alone has about 12 million (?) more people than Australia.

By the way... Didn't EVE pass 300k subscriptions a year or two ago and also get 63,170 players online simultaneously in January *edit*? That downtime isn't worrying them.