Fix data from Sensor

Hi guys,

I am trying to fix a data from my power meter. I have identified it measures 30% less than it has to, so I am trying to work as a man in the middle in order to calculate the corrector factor.

I am trying to use a Listener, but I think it is a read only way.

Is backgroup the solution to my problem? Is it possible to change a metric from a sensor?

Kind regards,