Stacking is an issue because it is not a constant weight increase. Depending on the bow, there comes a point where the increase may be 4 or 5# or more per inch. I love my long Widows because they just seem to keep bending without hitting that wall. I've pulled them back to about 33" and they still feel smooth. But I bought a beautiful 58" Bear Grizzly on Craigslist a few years ago (to give to a friend), and it stacked so bad that I was too scared to pull it to my full draw, as it felt like it would break.
If a bow is meant to be drawn to 28, all bets are off as to how it stacks after that, and whether the limbs can take the abuse.