How funny. Thanks for the information.
Now that I understand what is being talked about, I can't imagine putting something in the bobbin hole that would offset the bobbin, even a little bit. The reason I say this is because of my experience with generic bobbins that I got for my Bernina machine. The non-Bernina bobbins are just a hair wider than real brand-named Bernina bobbins and boy just that hair difference really messes up the sewing on it. I started having trouble with my machine and it drove me nuts. It would have a problem sometimes but not others. I finally took it to the dealer to have it fixed and right away he pointed out that I had the wrong bobbin in the machine. He could tell right off the bat because the fake ones had 7 holes in the bobbin, where the real bobbins had only six holes. He also showed me that the fake bobbins stuck up out of the bobbin case just a hair higher. If you weren't looking closely at it, you would never notice. So I got rid of all of the fake bobbins and never had a problem with them again.
When I clean my machine of lint and oil it, I put a drop (the tiniest of drops) wherever metal touches metal. This seems to make the machine sew more smoothly.
Oh, and all of those fake bobbins that I have, I use in my travel hand sewing purse. That way I can have the color I need and it doesn't take up as much room as a spool of thread. I now have a lot of colors of pre-wound bobbins for hand sewing. Yep, a whole lot of colors.