You all are confused. Everyone will get access to the update at the same instant in time. If it appears on the Apple servers at 10PST, that is just a frame of reference. Your local day/time at that instant will depend on your location, but nobody can get to the update before anyone else just because of their time zone. Sure, the Aussie may see the update post early on Saturday where he lives, but there haven't been people in New York downloading it for half a day before he could.
This is one reason all military computers use GMT.