Today, on my nice trip around Lake Tahoe, when I charged, I checked the labels on CCS chargers for a change. I normally only check level two because I like to charge my Zero SR at around 8KW.
But I was curious what voltage the CCS runs from, to see if 240 VAC is in them. The answer is NO! However, it is 3-phase 480 VAC, which means there is 277 VAC between any two wires at a very high current capacity. IOW, the voltage will not drop much under a heavy load.
So now I see the issue. EV chargers are normally good for 90 to 265 VAC input. 277 VAC is slightly out of spec and will stay close to that under load. But I suppose they could use a 1.2 to 1.0 step down transformer, and it won't be all that large for 7 KWs, and would make a negligible difference when somebody is DC fast charging. But I can also understand why they will not bother.
See label below from the new BOA CCS chargers at South Lake Tahoe. Four of them there, others nearby.
-Don- Reno, NV