Yep, the enthusiasm is more important than the HCA. You can see it at the first match of the season, when all the teams have the same shape and enthusiasm. If we consider 2 teams with a similar level and the team with HCA plays TIE and the other plays normal, I assume the team which plays normal will win in 80% of case.
(But I haven't done any survey, that's just my opinion, based on my experience in this game.)
PS: sorry for my mistake(s), if i did.