My thoughts as well; but there still might be some significance to the timing. It's possible, for example (and this is just conjecture, I obviously am not privy to Apple's manufacturing systems), that there's a "point" once per day where the days (24 hour) orders are handled. All who got charged today seem to have gotten charged at the same time. Which leads me to believe that the folks over at the Foxconn plant had a fixed amount of Macs they were going to produce in this upcoming 24 hour period. And, what I think is happening, is everyone whose Mac is going to be built in this 24 hour period was charged at the beginning of the "day".
It may even be that everyones BTO order was charged today, and then the stock models that are built will be charged when they are boxed and ready to ship; instead of prior to being built. Charging the BTO order models now makes a lot of sense; because it can kick anyone out of the queue whose payment didn't go through, and make more room for stock models so that they can get those machines into stores.