Body scan accuracy

I’m kinda just here to complain. I wish the body scans were more accurate, so I could get a better grasp on my progress. I just took one and my waist measurement is off by a decent amount. And compared to the one I took three weeks ago it claims I’ve lost 3 points of muscle.

If anyone has an app or system to input your own measurements and weight and get an accurate idea of how fat loss and muscle gain is going please let me know!