Please note that the guide you've copied this from is quite old and in many aspects deprecated. This, I believe, is one of them, because this is for DX9. In DX11 the antialiasing levels are visibly different (though I can't tell you what they actually correspond to, and I'm not sure if I ever saw anyone mention that).
There has been no update with dx11 AA information that I'm aware of. Perhaps Marcel will find this thread and help out.
The question was never answered even on S397 forums as far as I know (or - I never managed to find an answer, which is probably a more accurate description).
Google or your prefered search engine is your friend, try it sometime! https://www.gamingscan.com/what-is-anti-aliasing/
Only read your post and so that's what happens when you don't read the full thread. The link has some very useful info for many who don't know so it's not a total bust.
