It depends. If the 40@28" bow is short, or has relatively short limbs on a longer riser, it might be at the limit of where the limbs operate efficiently and when pulled past 28" it begins to stack. If so, then it definitely will feel a lot different from a bow that is designed for a 29.5" draw, even if they make the same poundage at that length. It could pick up 5lbs in that last 1.5" distance and will feel harder to pull than the bow that goes smoothly to 29.5" and gains only a couple of pounds per inch in the last few inches. If both bows are the same design, length, etc., and either bow will draw smoothly beyond your draw length, they will feel the same.