Ok, one more caveat about the above metric, Helpful rate.
As AI note writers scale to write on more notes, they need to process increasingly large feeds of candidate posts.
However, as the candidate post feeds grow larger, the % of posts that are actually in need of a note grows smaller (since the required amount of note request signal is largest in the Small eligible post feed, and smaller in the larger feeds).
Therefore, you can think of feed size as something like a 'difficulty level': you'll see the same AI note writer get a significantly lower CRH rate if it's processing a larger feed of posts, all else equal.