It is very true that the ranges are personal. When I got treated I had to be overtreated to show positive results. Not overtreated according to my body but according to their charts. I fall in the very, very mildly hyperthyroid range when I feel my best. But still I show no signs of being hyperthyroid like my blood pressure and pulse rate are still normal. If they treat me less, I immediately show quite severe hypothyroid symptoms.