It smells randomly

There seems to be some embodiments in which the model works. In my case it was a disaster, and this product simply unusable. Times it has something appears, then only error (the maximum weight the scales I'm good 70 Kg away). It does not work once and the next time. I was within two minutes weighed more than once. The results were as follows:

1. Result: 90.2 KG
2: Result: Error
3. Result: 89.8 KG
4. Result: 95.2 KG

At the 5th time I've asked myself for fun with my girlfriend together on the scales. Result:
99.0 kilos. Whether my girlfriend now 9.8 or 10.2, or 4.8 weighs, I do not know;)

Conclusion: complete flop. Either I have a broken part of getting this construct is simply a nothing.