I see your point. Think I’ve a similar situation, one pv plane facing north-east the other total opposite south-west The picture with comparison NE vs SW is below.
I’ve the luxury to compare the forecast against my inverter measures.
There’s no way in yellow mark in the morning that my SW plane is getting direct sunlight.
But I get the measures from my inverter and it’s producing.
There’s no way in red mark in the late evening that my NE plane is getting direct sunlight.
Again the measures from inverter shows production.
I think this has to do with diffuse sunlight which hits your pv plane rather than direct sunlight. Maybe @Forecast.Solar who owns forecast.solar service and is member of the forum can elaborate on that.
