I just pulled my SolarCity contract and it does indeed estimate 0.5% decrement per year (strictly, it's estimates are 1% ever 2 years). So the question is: who

I just pulled my SolarCity contract and it does indeed estimate 0.5% decrement per year (strictly, it's estimates are 1% ever 2 years). So the question is: who looses on this deal? My quick read is that they owe me a refund for any measured underperformance. Has anybody walked this dog out to see what their measurements are?