Upon reading his section, I realized something: his High 2-A key feat refers to being above any and all deities, when that's actually explicitly under his 'Ao's Avatar' information section in that book.
His Avatar needs upgraded to High 2-A since it's the avatar that can casually strip even Greater Deities of their power. The sentence preceeding it even leads in with discussing his avatar explicitly ("Theoretically, Ao's avatar can do anything"), then proceeds to detail examples of powers he has.
His avatar's next best feat is actually what his True Form key is, I'm realizing upon examining the evidence more thoroughly.
Deities aren't high 2-A tho, his high 2-A feat is transcending them.
Although honestly if even his avatar is above any other deity, i don't know if he should have a key for that to begin with, it looks more like he's simply getting a body instead of using an avatar that limits his powers.
There's probably more, but the main ideas are that Overpowers are vastly above Greater Powers. So either Ao's avatar becomes "At least 2-A" for being more powerful than every Greater Deity in FR or we remove both keys and only make him "At least 2-A" (unless magnitudes above the Gods still translates to High 2-A).
Again, is there anything implying that the avatar is weaker in any way instead of simply being a physical manifestation?
Because it really doesn't seem like it's something that needs a key, also because being completely beyond the other gods does imply that the power is the same and it's a "Ao creates a body" situation rather than having some sort of limitations.