Those estimated vg numbers will be changed to the real numbers you are seeing today. The guys do a good enough job using data to reach good enough approximations. They aren't in a position to point sales like npd and the other guys, but by the same measure anybody can see those numbers for free, instead of having to pay $20k pa. To choose to follow estimates because they might fit an agenda or whatever, instead of close to actual numbers seems like an argument to me.