"Wrong scales?"

I attended an endocrinology appointment and was quite insulted by what I was told by the nurse prior to my appointment. My height and weight was routinely taken before my appointment with the doctor as it has been everytime before any appointment. This time I was told that if I needed an operation I was not going to be offered one if I was in the obese category! I was also told I was ok as I was still in the overweight category, but I must lose 1 stone in the future I appreciate that I may be slightly overweight due to thyroid medication, but the actual scales in the hospitals were actually wrong as I did weigh myself both in Boots and my Gym the next day and it was 12.1 stone and not 12.9 stone as shown on the hospital scales. My BMI is 29.4 and not 29.7 even if it is still overweight and trying to lose at least half a stone. it is not helpful to be patronised by a member of staff just before a hospital appointment which most people do not look forward to especially as I am a regular gym member and everybody knows that muscle weighs more than fat which means BMI is not necessarily a good indicator of fat content.