Looks to me like they are anticipating a return back to PC's as the primary device for most users, Which does appear to be happening, By now everyone has their tablet, Everyone has their Console, Everyone has an expensive phone which they are already upgrading every time a new one is released so major sales times don't really come into that.
There are a number of reasons why any company could be holding high stock currently and I'd say now is a good time to do it with the move towards Windows Tablets and back to PC's becoming increasingly imminent.