If the meter is using an inductive pickup, I wonder if it can even tell the direction of power flow?
If it can't, and I fed my surplus power into the grid, the meter might actually go UP and I would be billed, as if I was the user, not the producer of that (backwards moving) power.
Having two 'dumb' meters wouldn't help much, unless you piped all your PV power out of your house via the extra meter, and onto the grid. Not using any of it in your home, except via your regular meter.
How they calculate the 'net' difference and deduct from your bill is another thing I'm wondering about..
That kind of two 'dumb' meter system wouldn't really work well, once people saw how easy it would be to steal some power. The more you steal, the more money you get back.. LOL!
I think the old style mechanical meter would be the best way to go. It seems like a good Net meter should work like the old style mechanical meters!
Edit:
Just found this:
Electric Meter for Net Metering ? - Solar Electric Discussion Forum by Northern Arizona Wind & Sun
"This is bad - I'm being charged for power I'm making!"