Ms skinniness

I just had my 6 mo appt with my surgeon and she said I was doing really great and that I only have 1 to 2 lbs to lose. I was looking at the BMI chart and it stated between 130 and 145. I'm weighing 159 on their scale and 155 on my scale with less cloths on. So I'm totally confused. Anyways she saids I could eat more calories because my 900 calories might have my metabolism slowed down. So I will work on eating more calories. Now it's time to work on toning and contouring my...