We are going to wdw from the 25th of Aug to sept 2. I'm trying to figure out the extended hours. On the Dis it says the hours at the park of the day is 1 hr early and 3hrs late. Disney's board says one hr early and up to 3hrs late. What can I expect. Are the parks nice at that time of night. Do the crowds thin out? Is there an extra cost for this?