Rankings question

The answer may be blindingly obvious but it's been bothering me for a while so here goes. Mewtwo is ranked number 2 with an attack stat of 300. The only mons on the list who have a higher attack stat are Dialga on 302, Palkia 308, Regigigas 315 & Deoxys a massive 345. As the aforementioned aren't currently in the game, Mewtwo should be at number 1 or am I missing something? Have tried googling the question & can't find an answer so over to you guys!