Every one of the IBU formulas is off, some of them significantly so. My advice is to just stick to one formula and through experience gain an idea of how bitter each calculated IBU value is. Then you can adjust each one to taste, rather than trying to get a number within a certain range. What...
seems like there are as many different opinions as there are replies to this sort of question. i would be interested in seeing an actual study on the subject.
nothing like plopping a few scoops of vanilla ice cream into a big glass of chocolate stout
if you pay close enough attention you can literally feel your lifespan shortening