flagstaad on 04 February 2011
I think Sonic is a bit undertracked, because those are numbers till December 31st, and in that date VGchartz has 1.21 millions sold on both consoles.
So the difference is actually:
(1.85 - 1.21) / 2 = .320 M units per platform in store shelves and I think that's more than the expected 10%. Not saying very undertracked, but it can be somewhat undertracked.
