When you FMQ, you are moving the fabric instead of the machine. If you can't do is a smoothly as the machine does, occasionally the bobbin will been seen. That is why with new quilters learning FMQ should use the same thread in both bobbin and top thread. That is what I was taught over 25 years ago. I upgraded from a older Singer from the 1970s to the top Bernina in the early 90s. There is the quality of the machines as there is between a Yugo and a BMW. It makes a big difference with the quality of your stitches with the quality of the machine. When you take your machine in for annual service, you might want to question the technician on what can be done to help you get the quality stitching you want out of the machine.