Mine Train running at reduced capacity in Sept?

[Saturn23]

I was looking at the fast pass availability on the Dibb site. The mine train is unavailable for most of the third week of Sept (supposedly a week of low attendance), yet there is still plenty of availability the earlier weeks as well as in August. Is this because there are fewer mine train passes in the off season? Do they usually run fewer trains during those times? It seems weird that mine train used to be available at less than 30 days a few weeks ago and all of a sudden it's fully booked for most of the week 60 days out. It's not just on early closing party days either.

 

[MataHari22]

Probably because that's when the MNSSHP start and the shorter hours make for less FP+.