Barthomeloi Lorelei is a Wizard Marshal, yes, and is the strongest official Magus in current existence. Aoko Aozaki, however, is not an official, and is not, however you put it, affiliated with the Association. The Association chooses to ignore her, afaik. So she wouldn't appear in the Association's powerlevel list.
And that Lorelei is equivalent to all 27 DAAs is certainly an exaggeration. She is just but as strong as one of them, not all.
When will I get my 1337th post?