Released in 2015, not sold in 2015.
what's your point?
..because mine is that vgchartz software tracking is massively off as evidence by them reporting larger sell-in numbers for splatoon than nintendo shipped thus making the comparision as flawed as vgchartz tracking wild guesses algorithum.
The point is that sales in 2016 are included in the numbers posted in the OP. For Splatoon specifically, it means that VGC numbers didn't exceed Nintendo's shipments.
Granted, VGC is only a few thousand units below shipment numbers, so their numbers are definitely too high. But your evidence is not what you believed it to be, and it would have looked worse for you if VGC had already posted numbers for more weeks in 2016 than only the two that are there.