$350 is a ridiculous amount. Most machines do not need yearly servicing anyway. There is another recent thread on yearly servicing that you might want to check out.
Unless there is something wrong with the machine, IMO there's no need to take it in for servicing -- ever! I do think that machine owners who never clean out the bobbin area or the lint from the feed dogs need to take their machines in for yearly maintenance; not the rest of us.
Years ago, when I used to take my Bernina 1230 in for servicing, it was about $125. I'm convinced this was basically for nothing.