Thanks to all for the comments.
If I'm reading correctly, there is only one drop to each residence, but a PoCo-controlled relay enables power through a second meter for reduced-cost night-time loads.
This, of course, raises more questions:
1. Why not switch ALL loads to the night-time meter? Unacceptable dropouts during the transfer (which don't matter to a heater)?
2. Why then would there be a "hot water" contactor in a distribution transformer cabinet that presumably feeds multiple customers?
It's interesting to see how the rest of the world encourages load demand leveling. (Quoting comedian Eddie Izzard at a U.S. performance: "You do know there are other countries, yes?") The dual-rate meters I've seen photos of in this forum make a lot of sense to me.
Here in Southern California, I understand that some utilities offer a discount to customers who allow them to install remotely-controlled contactors that shed high-power loads (e.g., air conditioning) at peak demand times.
