Resetting the BMS via a diagnostic tool is not really a thing on newer Mercedes, but I could definitely see a dealer additionally charging as much as the batter

Resetting the BMS via a diagnostic tool is not really a thing on newer Mercedes, but I could definitely see a dealer additionally charging as much as the battery costs to reset it on an older model that does need it. You can buy dongles and do it yourself, but not everyone is willing to mess with coding their own vehicle.