User blog:Flaminghorse/Aizen Spiritual Power

Why does every where I read about Aizen on websites say that he has twice as much spiritual power as an average captain-level Shinigami, but in the anime it said fusing with someone with twice as much spiritual power as captain-level Shinigami and in the manga it said higher than a captain class Reiatsu. Where did average come from it was not said in the anime or manga, so were did average come from. Is Aizen twice as powerful as the new Generation of captains or what?