On some of the lessons there is both a JAM track and an MP3 recording. Of the ones I have seen they are the same piece of music; I had hoped that the MP3 might be downloadable to iTunes/iPod as that would have been very convenient for practicing with but I cannot find anyway to download so I assume that is not their purpose.

Other than the technical source of the recording is there a reason (or purpose?) for the choice of an MP3 or JAM Station track?