If the power company grid meter is not a bidirectional one (no net metering), it only measures the amount of power flow through it, irrespective of either you are importing or exporting the power. So all the power feed into the grid will be added to your electricity bill.
So please set ESS grid set point to always trickle power from grid...
Next days I will make deeper analysis comparing the meter numbers and the ones in VRM.
Just to make others aware of it... I did not know it.... and I was surprised about my first power bill after installing an ESS system without netmetering.