Just an editorial note....
DME isn't a luggage delivery service, it is a guest delivery service. So, it doesn't matter whether or not your luggage is being handled by DME when it comes to reservations.
All guests that wish to avail themselves of this service need to make advance reservations...whether or not they are using the luggage delivery perk. Personally, I can't imagine not useing the luggage delivery part of DME. Perhaps I would leave my bags untagged and get them myself if I were arriving into MCO after 8pm. Otherwise, I let DME take care of them. It is soooo nice to just get off the plane and head to the DME counter and not have to lug those bags around the airport.