I'm glad I saw this thread. My '06 950 SM (6500 miles) has just begun to not ratchet back on some up-shifts, irrespective of gear. I had recently lowered the lever a little and I thought I was hanging the lever up slightly with my toe.
I just read through this thread, removed the jet and yup, it was plugged. I'm a guitar player, so I cleared it with the .010 string.
Thanks, Orange Crush. This is why SM owners need to read this section, too.