To be fair, a lot of rides did only at around 11am as very often testing was running late. However, A very realistic option which would allow Dreamworld to save a tonne of money but also keep customer satisfaction would be to operate rides on a weekday timetable similar to that of Rainbows End in Auckland.
Having 50% of rides operating throughout the entire day would be much better than having all rides operating after 11am and closing 90% of them past 4pm. A simple 10-1:30 and 1:30-5 timetable would ensure that there are plenty of rides open at a given time and they wouldn't be being closed all at once. The new operating hours are very, very random and confuse the hell out of me, given it's the most random rides open past 4pm (claw, panda and Madagascar ) customers are not going to know which rides are open past 4pm and there will likely be a lot of complaints in regards to this. A SIMPLE timetable which is UNDERSTANDABLE to the customer would cut costs on labor and operation expenses by miles.