This is a classic example of complexity leading to unintended results.
The pricing tiers were set up to encourage conservation. But it's a blunt instrument; my small house with 2 adults faces the same pricing structure as my coworker's larger house with 2 adults and four teenagers. He installed solar, and was very happy with the payback period.
Meanwhile, the system wasn't rethought when home electricity generation became both practical and desirable.
With luck, the obvious absurdities will eventually be fixed.
p.s. the comment at the top of this sub-thread was supposed to be a response to your earlier comment with "I don't know about the US", but got mis-threaded, making it look like I was playing Eeyore, and less like I was trying to add a wee bit of US data.