MK is open from 8 or 9am, (depending on EE), to 6pm on party days according to the link given above. That's 9-10 hours all day!! I think regular admission price is very fair for 9 or 10 hours in the park all day. If your concerned about MK closing early, try to get there early so you can soak up all the hours that it's opened.Too bad the ticket prices aren't prorated for day visitors accordingly.