Inaccurate noseweight gauge

In the present discussion on nose-weight many seem to have too much. I may have too little but I just don't know.

I bought an AM Controller Caravan Noseweight Gauge, anxious as a new comer, to get it right.

This yellow and red plastic thing sits on the towball itself and then you lower the van onto it and read off the weight. I did so, on level ground, Being new, I tried to (scrupulously) follow the various instructions related to taking such a measurement.

Apart from being very difficult to read unless you kneel in the mud with good specs on, it told me my nose-weight was 50Kg, So, I moved 20kg of kit into the front locker. The reading was still 50kg despite my pushing it down manually and releasing it, in case it was stuck.

This seems to me to be a potentially dangerous piece of kit.

Can anyone recommend a good alternative apart from taking my expensive and heavy (but accurate) glass digital bathroom scales with me all over Europe?

Thanks!