A true 1/4 inch has never worked for me, blocks always comes out to small.
Some smaller than others.
My machine even has a 1/4 inch setting but it dosnt work out either. Just have to move the needle a couple of notchs to the right.
If it is a pattern for a whole quilt it dosnt matter about the size. Just adjust the sashing etc to fit.
But if it is a block that is used with others who make blocks for a quilt, you must be exact.