EMH / FD / Park Hopper - will this affect crowd calendars?

[lovndisney12]

Crowd calendars are primarily based off of past historical data. We have had great success utilizing them to pick the best park for each day. However, we will be going the end of December and wonder if the FD promotion with park hopper (assuming most didn't go for water park and more option that time of year) will make it harder to more accurately predict the crowds. Also, will it make the EMH more crowded? We have the park hopper so can adjust mid-day if needed - but that could mess up FP+ and dining reservations. Thoughts?