Sorry booty, but I totally disagree with what you have done, I mean trying to guess vgc tracking ( or at least with the logic, that you use !)
For instance, you have assumed 105k for ps4 in March last week (from 108k last week, why such a tiny drop?) , for vgc it could be 40k though... You can't be certain for what vgc would show! This will draw a wrong picture of how much vgc might have undertracked or might have overtacked something.