The first post is for Hoosiers. I don't know much about them, but I've seen that most of their stuff isn't for drag, but autocross etc. I'm sure the M&H references are for the 23s, that do indeed measure out bigger. Funny thing about the honda tech link is that a post from me is at the top of the page lol.
Fwiw alot of slicks measure out bigger. Even the 22" MT's measure out 22.5.