How do you decode the serial numbers on Microsoft mice? Here is an image for reference.

I'm not sure what any of these mean, but I read that the four large digits are the date, although its format seems inconsistent. This one appears to be week-year, but I have seen some mice that apparently have this reversed.

I keep hearing that the G400S has smoothing due to the increased max DPI, though this seems to contradict with the fact that it's on the flawless sensor list. If this is not just a myth, how bad is it, and should I just stick with my worn G400?