Not to mention the fact that the Dessert Party is pretty much a meal in itself. The Dessert Party is best done following a late afternoon TS lunch or a VERY early dinner IF the party does not start until 9 pm or later. Basically, you need at least 3-4 hours from the end of your last meal until the start of the Party, or your stomach will be most unhappy.
And remember that there is no such thing as a 7:05 Dessert Party. No matter what silly staggered time the reservation system gave you, the Party starts for all participants 1 hour before Wishes. If Wishes is at 8 your Party will start at 7 and you should get there around 6:45 to check in. If Wishes is not until 9 then your Party starts at 8 and being there a full hour early is nothing but a waste of time. Tables are assigned as reservations are made, not when parties check in.