Is the Global Hardware Chart wrong?

[TWRoO]

Figures are adjusted based on new data.... in other words the X360 total for pre-2012 must have increased by about 400k between the two periods you checked the hardware gap.

If you go here: http://www.vgchartz.com/yearly/2011/Global/
you can see the gap at the end of 2011 is now ~3.5 million