We have to regard these figures as representing the energy you mean "Behind the meter". What we done here is estimate what the usage would have been, according to population, if there was no solar, and subtracted what was actually known to be used, so this is the "Behind the meter" energy you mean. I agree with you the figures are likely to be heavily revised, but one thing is for sure, these are massive amounts of money, absolutely having an effect on the value of money, devaluing it, until the funds representing it are issued.

Also, imagine what it means to utilities energy companies, effectively, when they have to pay out to compensate customers for creating their own electricity, it is like a shop having to buy back products it sold years ago. Their shareholder base isn't getting any less, so to keep them happy, they really have to price gouge what they do sell now, to keep shareholders happy, but it is impossible for them to keep doing that, whilst the solar continues to scale up regardless.