I may be the only one to have caught this so far but I believe there is a slight error in the article. It says:

"For Assassin's Creed 2, which featured PS3 predominantly in its marketing program, the needle did move back toward Sony and wasn't quite 2:1 but the advantage remained sizable at 795K to 449K."

which implies that Sony was the higher grossing company for AC2 sales, which is incorrect:

4. Assassin's Creed 2 (360) -- 794.7K
8. Assassin's Creed 2 (PS3) -- 448.4K

P.S. - If someone has already pointed this out please disregard my post.