The issue is that Disney has been waiting until the last minute to update their hours and extend via EMH. I think they’re doing it only a month or so out now. That’s likely what changed the crowd predictions. Longer park hours draw bigger crowds.
I can say that it was more crowded than expected after mid-September on this year. That’s continued into the new year. If you look at what the crowd levels were this past December, you’ll get a feel. I would use those levels, in conjunction with the predictions to do your initial planning.