Sara, what you are saying makes sense and fits in with what my dealer was telling me...about the foot/material bouncing and not allowing the stitch to be made. There fore a stronger spring also makes sense. Now that I think about it, my BSR did skip a stitch , only 1 once in a while while I was quilting at Christmas, but never gave it a thought, chalked it up to my inexperience. Also, I always tried to remember to set my presser foot pressure to 0, but most times forgot, so perhaps that is why I didn't have more problems. I have made arrangements to take my machine in to have the stronger spring and the update done while I use their machine for my embroidery club. Then I will be able to take her home with me. It is time for her yearly check up anyway.
Great research and info. Thanks for passing it along.