My last quilt finished perfectly as far as the width went....but the length was a whole two inches longer! It was even on both sides so I left it, I just had to work one more square into the final borders.
Next quilt I will use my quarter inch foot instead of trying to adjust the needle position. I realized halfway through the setting I was using for my scant quarter inch was just slightly different each time I turned the machine on.
I am amazed you were able to find and correct that difference, even on a finished top!