I have had this problem with a quilt that I was supposed to" just quilt it out". It will not quilt out. Hers was 10" longer on one side. Like you said you can take apart some of the rows and sew them back together for the opposite direction. You will not have to take all of them apart. I took some apart in middle, left side, and right side and then mixed them when I stitched them back together. It worked. Good luck.