It sounds as if the feed dogs need lubrication. How to do that at home, I don't know.
As for the store, that's a pretty typical dealership question. Sometimes it's because they offer special pricing or service to people who have purchased from them. If they will take your machine in for cleaning and servicing, I wouldn't worry about it.
Edit: Sometimes you can find a Bernina authorized service technician outside of a dealership. You might ask at quilt shops that are closer to you if they can recommend someone. The dealership that sold me my Bernina many years ago went out of business within a year. I was able to get it serviced at a different dealership, no problem. Currently the closest place for me to get it serviced is a quilt shop that sells Bernina machines.
Last edited by Prism99; 07-21-2017 at 03:16 PM.