As we all know, most of California, except the portion from Lake Tahoe north, is set at an angle. Like many places in the state, the streets in our community were laid out parallel and perpendicular to the railroad, and the railroad runs parallel with the valley. "South" is really South by Southeast, and that's the direction my solar panels face.
This obviously means my panels work better in the morning than the afternoon. That, in turn, means a significant penalty for the one-hour shift in peak time between E6 and E9.
Yes, the 3 cents/kWh savings of E9 over E6, midnight to 7 AM, is very tempting and if I intended to put lots of miles on my LEAF it would probably outweigh the one hour delay in E9 peak time. But I only drive about 7K miles/year, so I'm planning to stay on E6.
Besides, E6 off-peak is 13 hours on summer weekday nights, 21 hours on winter weekday nights, while E9 off-peak on weekday nights is only 7 hours year round. Since I am driving low mileage, I plan to use L1 charging only, and 7 hours may not be enough on some nights.
Like they say, YMMV.