Hi, I'm busty and have been at a great weight for my body (height and proportion) for years now. I have been over weight before and I used to believe I was horribly obese because of the BMI scoring system. it doesn't take into account how much of that weight is breast tissue and muscle (organ) vs fat (fat or "extra weight").
If I were to tell someone right now that I was overweight, besides my mother (who has her own body insecurities that she projects onto me), they'd think I'm crazy.
BMI is what influenced my doctor (when I was 15yo) to explain to me that I needed to cut down on sodas, chips, anything that would break down into simple sugars, even though I had cut those out of my diet 6 months prior to that and had already lost weight. It was humiliating. I went to a wholistic health practitioner and learned when I was studying anthropology that science isn't an exact science. A lot of it is influenced by the cultural beliefs and values of the scientists themselves. No matter how much we want to believe that there's no bias, there is always something.