I think I understand what your saying.

So it would be correct for me to say that my bow has a listed IBO speed of 290 if it were at a 30in draw even though the shortest I could make it is 31.....right? I just need to apply the 10-12fps gain per inch that it is set at and I have the actual IBO of the bow (not to be mistaken for actual speed of course.)

Right?