Yes on the later question. In northern CA, they also offer "EV" plans where there are no more tiers. The base rate is higher (11cents/kWH after 11pm, peak of about 35cents/kWH during the day) than the tiered system (which starts at 5cents/kWH after 11pm with a peak of ~15cents/kWH, but grows exponentially).
But if you're charging an EV, you'll likely blow past the tiers anyway so having the EV plan works better. With a Model S, at least, you'll really only need to charge it at night and the software lets you schedule charging.