Which of these indicate 80% charge?

A Leaf being charged is not subjected to any substantial loads. The way that the BMS on a smaller vehicle gets around variance in voltage is by averaging and by lagging in what it reads. It's the equivalent of the circuit in an ICE fuel gauge that stops the gas gauge needle from bouncing around as the fuel sloshes in the tank.

SageBrush said:

As mentioned above, the voltage discharge curve is affected by load, temperature, hysteresis and no doubt other variables I am unaware of. These variables are more noise than the change in voltage in the middle of the discharge curve. This is why SoC meters based on voltage stink, and coloumb counters are needed.

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I was thinking more about the charge cutoff. I agree that while driving, coulomb counting is probably the way to go to maintain some semblance of accuracy regarding state of charge. In my personal experience with a Lithium Ion project (lawn mower), the charge algorithm was constant current until voltage set point, followed by constant voltage as current decreased to a cutoff point. While operating, I used an amp-hour meter to determine remaining capacity.