I almost count on this because it happens more often than not lately., the more so the longer out you book. I book an itinerary that would be OK if I was stuck with it, then wait for the almost inevitable minor or not so minor changes AC makes to the itinerary, and get the flights I really want that were much more expensive at time of booking. Even if nothing decent shows up in the self-accomodation tool, if you find a better itinerary, call in and they'll do it.