I rounded up. I just redid the calculation with a sharper pencil, and it looks as though I’m paying a marginal rate of about 10.4 cents per kilowatt-hour.
Not that ti really matters, but I had no idea others were paying so much.
According to energysage website, the national average is 19 cents per kilowatt-hour. California is 33 cents/kWh. Ouch.