I had this problem too. It was (like you) driving me crazy! I bought two books ...nothing. I was complaining to a lady at the quilt store and she was a teacher who gave me this very tip. Who knew?
She also said that I should always use a scant 1/4 inch seam on all my piecing, that she gave this tip to all her students. And that the pros were always in the habit of doing this for acurate piecing. Kind of maddening huh? When you buy a 1/4 inch foot, why don't they just make it scant 1/4 inch?? Ha ha ha .... Oh well the rant is over girls. Sorry .....