For what it is worth - getting hot under the collar about solar generation fraud is quite meaningless provided the panel wattage installed is properly verified.

Day to day output is variable,  month on month is just about static, but year on year for a given location is almost a constant - give or take some cleaning, climate change etc.

You do need to take into account the geography - for instance my Auckland 4.2kW will not have the same annual output as an Arizona 4.2kW.

Each installation will have its' slight output variations from the one next door, shading / inverter type / panel type / orientation - but these are pretty much fixed once the system is started.  

My panels have averaged 15.8kWh / day over the past 1656 days since install, with max / min annuals at 16.2 and 15.6.  I fail to see why there is all the fuss, unless I have missed something...

BTW - checkout : paladin.nz for the latest in excess solar recovery to hot water / storage heating / pools and EV charging.

T