^
1.1 million is also an estimation by DFC though. Unless you think DFC is more accurate than VGC, I don't think adjustment for undertrack is necessary right now. Probably wait more sources before we know for sure if VGC undertracks ME2.
MikeB predicts that the PS3 will sell about 140 million units by the end of 2016 and triple the amount of 360s in the long run.