While my system regulates feed-in based on "sum of all phases" just fine, all energies shown in VRM seem to always be based on the single phase sums. Unfortunately this also makes many other graphs useless like the consumption diagrams.
Currently the only workaround I know would be to purchase and hook up an external EM24 meter.
This issue has been discussed in other threads already but I couldn't find any info if this is going to be implemented.
One way to approach this would be to enable alternative sources for the consumed and fed in energy to pass on to VRM from the GX - no need to mess with the actual regulation which seems to work perfectly fine with the built in sensors of the Multis.
This is how I would see it work:
All the electronic meters installed today have an IR interface where you can read out the energy sums.
There are inexpensive readers for this based on Tasmota which provide the energy sums and more data via Wifi and MQTT for example with a one reading per second cadence, see this screenshot from a recent Westnetz device type ZPA.
I looked into this already but could not find the vrm logging scripts anywhere on github.