Now, take this with a big grain of salt, but... It was explained to me once by a Soarin' CM in the pre-show area that the DCA version was built with very expensive "clean rooms" that house the IMAX projectors above each theater. It's a system where all dust and minor particles are kept out of the projector rooms via a pressure gradient and advanced filtration system. It's expensive to install and expensive to maintain, and it ensures the film quality stays very good in a film system that is running continually, in addition to WDI coming in several times per year and swapping out the film itself for new prints of the film. This same DCA CM stated that the Epcot version of the ride was not installed with this same IMAX "clean room" technology, but rather a more standard and cheaper HVAC system with a filter, and that is why the Epcot films suffer faster and more noticeable degradation of quality