My experience Wednesday and Thursday this week at Epcot and HS has been that the actual wait times are between the official and Touring Plans times. As someone mentioned before, I've had several incidents of moving towards a ride because the wait time is low, only to have a swarm of people go in before us; and I've wondered if Disney had just adjusted it's official wait time and everyone rushes over. Then, the wait is much closer to the Disney posted time than TP. We headed towards Slinky last night for 22 mins TP, but it shut down as we approached. I was watching, and when it re-opened, Disney listed 40 and TP listed 29. Turned out be 45-minute wait. I don't think TP was able to adjust for everyone rushing when they saw it re-opened. MNMRR also was posted 45 on Disney and 20s on TP, and the actual wait was 45. We rode this during the period that Slinky was down, which may have been why it was so high. Smuggler's Run was between the official and TP, I think about 35 mins, but it felt shorter because there is so much to enjoy while on line.
Maybe just a hunch, but it also seems like loading goes a lot slower on many rides. We breezed through the Soarin queue Wednesday, but the section of feeding us into the boarding groups and then strapping in seemed to take MUCH longer than usual. I think this depends on the cast members too.