Right place? MeasuringNegative energy back to grid

Hi, I'm a customer for at least 7 years.
3 phase accumulator heating 10-18 kW on port 1-2-3
2 phase home electricity 2 phase, port 4-5
36 solar panels, 1 SMA SB convertor + 1 IFUBAT battery (spreading the load over 12-24 hours),
water consumption meter p7
I should like to measure electricity streaming back to the net. Because of the newly installed battery it should not exceed 10-15%. It was around 50% some months ago.
I use the same clamps during the night (accumulators ) and day (solar energy).
Solar energy is now almost completely gone on the graph due to battery loading of not consumed home electricity produced by the solar panels.
But I don't have any idea what is still moving to the grid.
Within 6 month together with the newly installed digital meters there will be some kind of taxes on negative electricity (they call it non-green energy)
Today the analogue meter is turning backwards, reducing number of kWatt.
Should V3 Flukso solve the issue? Can I reuse the p7 (p6) pulse1 0 signals?
Any advice appreciated.
Marc.