When you got the email explaining that your numbers had been adjusted down, did you click the link at the bottom directing you to their explanatory blog post? There have been quite a few posts lately on this board that make me wonder if a lot of people are not reading the explanation, only the numbers. Thus the confusion...
As explained in their blog, when TP downgraded estimates most recently for the fall and winter months, it was because attendance in the parks this Summer (and for Toy Story Land) have fallen way short of expectation. They are guessing this might be because people are delaying their trips until the opening of Galaxy's Edge next year. Hence, they are predicting that crowds this fall/winter will be lighter than usual. Also, October has been a very busy month in recent years. So, it makes perfect sense that your mid December trip would have lighter crowds than what you had experienced on an October trip.
Hope that helps!