That's not a mistake. They need to be between two and six. That means that if you have three competitive moves in your level-up list, you must limit your competitive egg moves to three, not four. And if you have four competitive moves in your egg moves list, you must limit your competitive level-up moves to two, not three.
HOWEVER... the guide to create a Pokemon movepool is just that... a guide. It means that if we deem that we should make exceptions, we can. We might have to make an exception for this CAP... although I'd say to try to keep within those guidelines if possible.
I just realized Heart Scale moves count towards competitiveness. Oops. There has to be an exception for this one because it's going to be more nerfed than it already is.