BMI Calculators vs. Reality

Hi All, Just a bit of curiosity info for ya all. We've all used the BMI calculators everywhere, including here. When I saw the surgeon the first time, my BMI (based on Internet and booklets) was 42. Now it's 34, again by online calculators. Now here is reality. My surgeon's office has a high-end scale that calculates BMI as well. My first visit my BMI was 50 via the scale and now it's 44! Quite a bit of difference isn't it?! My overall goal is to reach a BMI of 22 - right in the middle of the range for someone my height (5' 6.5"). I'm going to try and rich my goal via the doctor's scale and I need to try and see if there is an affordable BMI home scale available since they seem to show a better picture of your overall health than straight weight/height. Just someone else here may find this of interest as well as me. Dawn