As PLB said. You don't. You just use the rating to comapre bows against each other when you are looking to buy. In te normal world a bow that has a faster IBo rating will be faster set up for hunting, too, assuming it has a similar setup. And as you have stated. It ain't a big concern to you.

Thanks for all of the replies folks.

I guess then the IBO rating that was listed on the bow when I bought it was performed with the 30in range cams (set at 30in) and not the set of cams (31-33) that are on it. I just have to do the math in order to figure out it's particular IBO right?

Sounds right to me.....I think