How to assign energy meter to EVCS

As most of us know, energy measuring of the EVCS is not very accurate. Even with configurated compensation within EVCS Setup.
So I decided to install an energy meter to get accurate readings for energy consumption of my EVCS.
When I assign the energy meter to be an EVCS, there will be two EVCS‘ in my setup.

How do I assign the energy meter to the existing EVCS, so both devices are shown „as one“?