I have read that the accuracy in cutting these days does make some difference too. A simple 9 patch can be any size seam you want as long as you are consistent. A block that has 1 seam on one side and 3 on the other has to have a seam that measures to your finished block. I am getting better with scant, but I always have to sew a bit and then measure what my finish is going to be. It's just more to add to the challenge. I am sewing a log cabin precut kit right now. I know where the seam has to be on my 1/4 inch foot and where I have to move the needle, to get a size that the next log will fit perfectly. A true quarter inch is too big a seam. The scant is 2 threads less and when I move the needle 1 click to the left, I am perfect. And, I have to make sure I am running the material right at the edge of the foot. Sometimes all this stuff just drives me nuts, but I just get over it and continue on.