Hi,
As an opt-out customer, I also received the letter from PG&E that the meter would be read every other month and estimated for the month it wasn't read. I also had a long conversation with someone from PG&E to find out what the estimate would be based on. They gave a pretty vague answer about "prior usage" (ie: last year's usage). When I got the letter, I decided to read and record the meters myself, which I learned on their website. I asked them for their most recent readings, which were done on 4/16. Then compared them with my readings done on 4/18 and 4/24 at about the same time each day. I was doing it correctly. I was told I could call in the readings on the meter reading days. They're going to send me a "meter read schedule". I will call in my readings on the next read day- 5/15. Then they told me to call back a week after that (5/22) to verify they recorded it properly. I can call the numbers in to their direct (smart meter) line at 866-743-0263.
Hope this helps a little more.