Me too. While the volcano itself is cool, it lighting up with LEDs at night is nothing super-impressive. I thought there was gonna be a night time "show"
I'm sure the plan wasn't to keep it open at night outside of peak season... and for IOA, my understanding is they rent out the park for private events at night quite frequently and thats the reason for closing earlier. I know I've been invited by 2 companies my family has worked for that do annual events for, my university had an annual night there, along with Grad Bash in high school, etc... it at least seems like all the time where OA is closing at 6 or 7, its because they rented out the park for a private event.