Apparently you don't since you admit my bodyfat weight hasn't changed hence yes the percentage will have gone down if I have gained weight be it water or muscle just like Muntzer after a show. Fluid is not fat. You are being fooled by subcuteous water I have no fat on me
as you know, I have the same scale as you do except a newer version. In my opinion it is anything but accurate. I've reweighed myself 10 minutes after the first time and the results are markedly different even though I didn't eat, drink, shit, pee or exercise between the first and second weigh-in. Also, supposedly my left leg has about 2-3% more fat than my right, which varies each time I weigh myself. If I exercise before weighing, the numbers change....which would be great if I actually did enough exercise to make a difference. Pretty sure 15 minutes of bodyweight exercises doesn't increase my strength as much as this device says it does. My BMI varies between 24 and 34 from one day to the next.
Please don't think I'm complaining because I am not. I like the scale. It's varied output is interesting to monitor and I use it almost daily. The one measurement that is the most consistent in visceral fat which hasn't changed since I started using the scale.