They may be making modifications if they're any complaints regarding the update before they release it to everyone. And could be that when it is massively released it will even better. I kinda think that this may be a component of gingerbread testing to see how it functions and possibly release gingerbread. This is just my thought about what might be going on. I don't have anything to base it on other than they released it to apparently a small amount and are seeing what the responses are to it.