Most bowyers don't change much if anything in their lamination layup for a relatively standard weight and draw length. If you ask for a bow that's 42#@27, most will make their 45#@28 bow and mark it 42#@27. On the extremes, some bowyers will change the lamination layup(No of lams, thickness and/or taper) to give optimum performance at your draw length, but not really in the middle. Of course, they already have figured out what the best combination is in the middle so you will be getting as good a bow as they can make, whether you order the poundage at 27 inches or 28 inches.