I ended up fixing the pen myself. It works well now, but after that experience, I am done with Goulet.
As I said nearby [1], when I had Decimo trouble, he not only got hold of Pilot to find out they don't sell an OEM o-ring, but after that spent the day back and forth with me via email, making and giving accurate measurements of an intact part, all kinds of things. The end result is still the first pen I reach for all day, every day. I don't know what was really so different between your case and mine, but I doubt it had that much to do with Brian.