I thought that VGC estimates *sold through* units, which is why they're a bit lower than what the manufacturer says.
If you recall, Nintendo announced that they sold over 3 million Wii U's by end of 2012, but VGC has 2.2million. Nintendo publishes shipped numbers I think, which is why in Apr~Jun they announced that they sold (shipped) almost nothing, as stores were still selling through their stock.
MS also announces *shipped* numbers I think, so when they say 3.2 million you have to take account that there's lots of unsold stock in shops now.








