I'm thinking they're just sitting on the hours until they see if the After Hours tickets sell out. If they do, then say bye bye to late park hours for at least two nights a week on top of the EMH night.
And if that happens, late evenings at MK on non party nights for Sep-Dec will be non existent. They'll all be party nights, EMH night, or hard ticket After Hours nights. (And the Dis doesn't provide an emoji for what I think of that)