Thanks for the explanation, I understand completely now. I have a very funny story about a quilt that I quilted for a friend many years back. It literally was a parrellogram because it was so skewed. I loaded it on the machine and after the first few passes I saw the problem. I took some pictures and sent them to her to ask how she wanted me to proceed. She said go ahead and quilt it and I did. She turned it into a dog bed (expensive dog bed) and said she would chalk it up to experience. I had started with the regular extra 4 inches of backing on the top left and at the end of the quilt there was no extra backing on the lower right side. We still laugh about that parrellogram quilt. She is a much better piecer nowadays.