VGChartz sales data is about as reliable as asking the 18 year old behind the counter at Gamestop then adding a random number to his answer.
You must have a personal vendetta against them or something to keep harping on with nothing to back it up.
In a post linked today, MCV states that there are now 38.1 million PS3's sold worldwide. Considering that the data on VGChartz hasn't been updated (states 36.1 million), and the PS3 sold 2.4 million units in the last quarter, VGChartz info is pretty damn close. Nobody (except for you maybe) expects the numbers to be perfect, only Sony has those.