Damn! Someone beat me!
Guess I'll just have to have a few points of speed this weekend and sort that out!
...But seriously, I know I'm extremely thin, but I don't consider myself unhealthy. I think each of us would know whether or not we are underweight/overweight and whether or not it's a problem. This kind of guide only provides some information, it doesn't determine if we're unhealthy...
However, the results of this formula could tell if there might be some problem. For example, if I was constantly feeling run down, and was worried about never being about to put on weight, and concerned about my image, the results of that formula would give me a stepping stone to go see a GP... I would then let them tell me whether I had anything to worry about, but would certainly not panic because of one little test...