but I do think the books themselves contradict this list of levels. Semirhage's strength was not remarked upon by any of her captors, and if she was as strong as Lanfear that seems like a big miss considering how often we've heard that being stronger than Nynaeve is so rare that would get remarked upon. Cadsuane as a level 5 also clearly doesn't fit within the context of the books as we were told that the wondergirls were stronger. Overall I think the spread between Elaida and Daigian is too small and Siuan's new level doesn't at all jive with the books. Also Annoura was strong enough to open a gateway, she burned out doing so while exhausted so she'd need to be significantly higher than she is placed on this list.
Cadsuane, I will give you. There definitely are quotes to the contrary in the books.
But they may not have remarked on Semirhage for a simple reason. Alivia was already around them, and at the same strength level.
As for where Daigian is, I think that is spot on. 37.5% of 72 levels is 27 levels, and since we know 37.5% of the population is too weak to be Aes Sedai, Daigian's position seems exactly right, at that threshold. Aes Sedai strength thus spreads over about 33 levels, which seems perfectly reasonable to me.