BMI is very much a numbers game, and half of that game you can't control. We can only alter the weight side of the equation. So, that means that many people who weigh the same or close to the same amount will have different BMI's.
Case in point: My 6'2" brother who weighs about 275 is considered obese, whereas I am morbidly obese at 5'5" and 281 pounds. I have to get all the way down to 239 to be considered just "obese." At my height, I won't hit the "overweight" range until I get below 180 -- more than 100 pounds less than I weigh right now! Even worse, a "normal" weight range for me is between 112 and 149. What the
On the other hand, at my current weight, I would be considered normal if only I could grow two feet taller.