There are a couple of other things that shrink the block besides the 1/4 inch seam.
I have used too much starch and ironing. It shrinks the block. Be sure there isn't any fabric left in the seam allowance when pressing. That can shrink the blocks too.
Yes, I have cut down to square up if needed. You should see the points on my first sampler cut with the AQ dies. There are lots of points missing. Even with the 1/4 guide, I still miss the points sometimes.