You are right. I remember I tried it according to arrow, but i couldn't take good results and i used it like video. I think producer sticked it wrong. I made a beginner project. I wanted more accurate results but i need to calibrate scales in almost every scaling. Offset value is changing permanently. It is annoying. Calibration is a little hard and time consuming. I could write extra codes to automate calibrating for arduino but it was a beginner project.

 If you calibrate often you can take more precise values. 
I think it is important choice of load cell max weight capacity too. If your max weight will be 1 kg, you must not use a load cell of 20 kg. 

In my video i scaled 8 kilos with no errors and others have %0.2 percent error rate.  

But i calibrated it just before my recording