Grats to you for figuring out the problem!
Not quite the same thing but I used to work for engineers, we always had pads of graph paper around and there was a big stack of spare pads. I used them to help with some fussy piecing and didn't find out until way too late that it had 5 squares to the inch instead of 4 (which is why there was a big stack of spare pads, they were wrong for our firm)... So the ruler cut and the paper cut were just never going to be happy. Oh, I got them all together but not one of my finer quilts. Still, the big goal was to go with the tulip sheets I truly loved and they outlasted the top.