Why does my Solar PV Inverter Read Higher/Lower than my Generation Meter?

Having had solar panels installed for nearly a month now it has become clear that there is a difference between the readings from the Sunny Boy inverter and the Landis generation meter so why does my Solar PV Inverter read lower than my Generation Meter? Other people have reported the opposite - that their Solar PV Inverter reads higher than the generation meter?

The reason is that the inverter reading is an estimate based on the electricity it produces but is not an accurate reading of the output. In contrast the generation meter is a calibrated piece of equipment that has to meet certain tolerances and is tested to ensure that the meter is within these tolerances before it leaves the factory.

So the reading on the generation meter is the correct one and the inverter output reading is to give you a good idea of how the panels are performing at any given moment in time.

At present our Sunny Boy 3000HF inverter is showing a reading of 96.1kWh produced but the generation meter is showing 98.33kWh which is just over a 2% difference between them.