In AC coupling system, how to calculate the real on grid power?

The actual grid power is from meter 2, and the on-grid inverter power is the difference between meter 2 and 1. About more AC coupling system details, please refer to this link:https://km.solaxpower.com/preview.html?fileid=0b2b2567-ca91-4a95-b08d-7f6c5cc9c8ab