I think it falls into the category of Old Wife's Tale. Real world experiences say regular deep Supercharging doesn't have an appreciable effect on battery health or life. At supercharger sites, there are places that have both 140 KW and 250 KW chargers. In Primm, NV there are 42 stalls. Maybe six are 140 KW. Have seen a couple guys charging at the slower stalls when more than 20 of the 250 KW are open. I guess they are doing what they think best.