"Is the shuttle code open source by any chance?"
Art Fenerty is the originator of the SP2 code, I just modified (added) some stuff to it. It would be up to him on that question.
I would think though, if your using it to make money with or modify to a product your selling that you should give
some kind of fee to "ArtSoft" per use or sale of a product based on this. Art put A LOT of time in this thing, I added some time,
but mine was just standing on the shoulders of a Giant.
You could also ask Brian (and he could ask Art), about how they want to handle that situation. For my part that I added/modified, it is open source which is only a very small part of the entire plugin.
Scott