Your manual is indicating that the gears are sealed; this is why they don't need lubrication. Since your machine is running fine, I wouldn't take it in for servicing -- especially when it takes so long. If you clean out the bobbin area regularly and oil the hook regularly, you should be fine. You may be exaggerating the fear of lint getting into areas you can't reach, especially if you have made only one quilt so far. I'd be more concerned about that if you had completed 20 bed quilts, although even then there would probably be no internal lint issue if you have been cleaning and oiling the bobbin area faithfully. I stopped taking my Bernina 1230 in for servicing over 15 years ago after paying $150 for basically nothing. I noticed the technician had not even bothered to return the top tension to factory setting, which is something basic he should have done in order to test stitches and tension. My machine still purrs and sews the way it did 15 years ago and I have approximately $2,250 more dollars in my pocket today to put towards another machine some day. In my experience the older machines simply do not need yearly checkups; however, I would take my machine in earlier rather than later if I noticed it starting to get "sick" or misbehaving.
Edit: Sorry about the manual comment. I was reading on my iPad and probably mixed up postings. I'm not sure if your machine has sealed gears or not. What I would advise doing is joining a Yahoo group for your brand and type of machine. They can give you lots of good advise about maintaining your machine and may even be able to recommend a good servicing agent in your area. You didn't mention what model you have, but at 20 years old it would probably be considered a vintage machine. Here is one Yahoo group you might want to join:
https://groups.yahoo.com/neo/groups/...gquilters/info
and there are additional groups specifically for pre-1980's machines, Designer 1 machines, etc.