I've gained over 20lbs since I got this thing implanted in my arm. My BMI is now 32. I've read that it's not as effective in overweight women, but can not for the life of me find out how less effective it is. It has also sunk into my arm more (presumably from gaining so much weight), I can only feel it if I press down hard. Would that effect the percentage too? The dr. that put it in won't answer my questions and is really rude.