You've almost got it, except the HPWC is not DC charging - it is a plain old boring EVSE (see my prior post on page 5) that delivers 240V AC to the car's on board chargers.Thank you so much for explaining it. It makes a lot more sense. So "chargers" like Superchargers, CHAdeMO, COMBO, and (HPWC too - not sure if this is included ??) are DC since they can convert AC to DC and bypass the onboard charger. L1 and L2 chargers use the on-board charger. Some L2 chargers offer up to 80V so it'd be useful to make use of Dual Charger option since the single on-board charger only handles up to 40V.
Also, you've used "40V" and "80V" - you mean 40A (amps) and 80A. L2 is always delivering 240V (nominal, ignoring commercial 208V 3 phase) - the voltage is constant, it's the amperage that varies.
In the plumbing analogy, voltage is the "electrical pressure", equivalent to the water pressure in a pipe. Amperage measures the number of electrons flowing through the wire (think the amount of water coming out the faucet). Water pressure (in PSI) and flow rate (GPM) are different, but related - increase the PSI and GPM goes up. Increase the pipe size (wire diameter) and GPM (amperage) increases, etc.