I would expect to hit a low in the crowds this week, followed by slight increase in crowds for the week of the 13th, increaseing crowds the 20th, and a good size crowds (not summer but the high side for the low season) the last week in September.
Prediction (BTMRR average waits no rope drop)
Walk on this week to 10 minute waits (schools just started for everyone)
10-20 minute waits for the week of the13th
25-30 minute waits for the week of the 20th (some fall breaks here???)
40 minute waits for the the week of the 27th (combination FWW and free dining)
Hotel booking/non-avalibility increase throughout the month of September peaking the last week.
Prediction (BTMRR average waits no rope drop)
Walk on this week to 10 minute waits (schools just started for everyone)
10-20 minute waits for the week of the13th
25-30 minute waits for the week of the 20th (some fall breaks here???)
40 minute waits for the the week of the 27th (combination FWW and free dining)
Hotel booking/non-avalibility increase throughout the month of September peaking the last week.

not sure... 

I could have picked ANY week in September and just my luck I pick the BUSY one



Their trend in crowds is going the opposite of yours. I thought they took hotel bookings and stuff into consideration when they do their calendar. 