I recently bought an Index S2 Smart Scale after having an Index Smart Scale for several years. I have been weighing myself on both scales at the same time to compare the metrics. All of the user settings (including Activity Class=7) are identical for both scales. Here are the ratings I get:
Index Smart Scale
Weight = 81.6 kg
BMI = 23.6
Body Fat = 17.4%
Skeletal Muscle Mass = 32.3 kg
Bone Mass = 4.8 kg
Body Water = 60.3%
Index S2 Smart Scale
Weight = 81.6 kg
BMI = 23.6
Body Fat = 25.3% (!!)
Skeletal Muscle Mass = 32.2 kg
Bone Mass = 4.1 kg
Body Water 54.5%
Note the huge discrepancy with Body Fat % and the smaller differences with Bone Mass and Body Water. I suspect my true BF% is probably in the middle. Why such a huge discrepancy between these two scales?