The problem is they do not preclude a single 20 on a 15a circuit. It seems NFPA does not even acknowledge the NEMA standard so
"load" doesn't enter into it. They do have the unenforceable limits on what a user might plug in but the installer and inspector are long gone by then. I guess they just want to be sure the receptacle won't burn up and leave it at that.
In the 23 code the draft I looked at even removes more language from 210.21. "Not greater than" is gone from the 15a row of the table even for multiple receptacles.
I think some of the changes in the 1st draft might not survive the comments tho.
They changed 210.12 to pretty much say AFCI shall be provided without listing any particular circuits that it applies too.
