Z-Wave:Fibaro Wall-Plug FIBEFGWPF-102: no value for meter_watts

My Fibaro wall-plug has a correct reading for sensor_power and meter_kwh, but not for meter_watts (always 0).
I am using OH2 official (2.0), with Z-Wave official binding.
I was adding the meter_watts just for info because I do not really understand the difference between sensor_power and meter_watts. Both should give the actual reading in [W], right?
Maybe somebody can explain…

Anybody…?

Did you find any solution?

No, unfortunately not.
Actually, I am simply not using meter_watts…