I have used magazine cutting charts and there are generous cutting requirements but not so much that you would say you wasted your money. You get enough for shrinkage and straightening the fabric and then a mistake or two. I have never thought yardage charts to be overly generous.
peace
My friend measures every cutting requirement to the 1/4" and never buys more than she absolutly needs for a project. Then after her first mistake she runs around to every shop in the area looking for more fabric. She thinks she is being penny wise, I say.......... no scraps in her bag