Fantasmic times in May question

[Joannelet]

I was looking at the schedule for Fantasmic for May from Intercot and I'm not understanding what is written there or if it is a mistake...but here is what is listed:
Disney's Hollywood Studios

Fantasmic!
May 3,6,7,9,12,13,15,17,20,22,24,26,28,29,31 -- 9:00 p.m.
-- 8:30 & 10:00 p.m.

How is it at 8:30, 9 and 10? Is this possible?

[MOJoe]

What that means is that all shows are at 9. There are no nights where 2 shows at 8:30 and 10 are scheduled. However, based on crowd and resort levels, Disney frequently changes the offerings for Fantasmic to 2 showings a night.

[Joannelet]

Thank you so much!
I don't understand why they wouldn't just put 9pm. (and leave off the 8:30 and 10pm unless they are added).