Appreciate might have veered off of your original post but was just picking up on a few points since. I completely agree, why the dickens are we measuring BMIs?? There are many a BMI compliant person out there who couldn't run for a bus let alone pass a fitness test.
The RAF have always insisted on differences for males and females for the RAFFT but the bog standard BMI chart makes no differences for the sexes, even though males will generally have a higher BMI due to muscle mass.