We have done the tour twice; the first time was in May 07, we view the rooms and fell in love, my husband and I were certain that we were only viewing and not buying, we were not prepared to buy, they needed our passports so we arranged to go back the following day. Before we left for ice cream our DVC guide gave us fast passes and took us back to Magic Kingdom, they worked all day. We went back the following day to buy and it was a our last day, we did all the paperwork and had ice cream again but we didn't have tickets to go back into the parks, they gave us $30 on gift cards instead of fasspasses.
The second time was May 08 and we were given fastpasses, if I remember correctly we used them throughout our stay, we only used them on rides we really wanted to go on and that had a really long que like Sorin, we did Sorin a couple of times over a couple of days with the fasspasses.
I hope this answers your question. The fasspasses give you an instant time to enjoy the ride rather than coming back hours later.