Pan, in both stories, was a god with a soul for music. For they both have their differences, but they both travel back to being a music freak. He overpowered women and seduced them, until he met musical instruments.
The differences in these stories are very clear. In "The Musical Instrument" Pan seems a lot more forceful and frightening. Which, in the Myth, this is not true. He did use sexual powers at his advantage but he was a very knowledgeable god.
This was my answer to the question when i took the test. I'm fully aware it is VERY late but for future students, I hope I helped.