Thank you all for responding, let me try to clarify.

In the 2022.1 version I have the three phases for both usages and return, right?
So in a script I can do the calculation of the nett result:
nett_energy_usage_result = (0 - ( p1usagel1+ p1usagel2+ p1usagel3)) + p1deliveryl1 + p1deliveryl2 ...

I'd like to suggest a few enhancements to the p1meter plugin.

Background for my request, imagine the following extreme situation:
L1 has a one phase solar panel convertor connected, this is where all the return happens
The house has all the power usage on L2 and L3
-> Nothing of the solar energy ...