very helpful comment: they could use the price to actively deter drivers from using the charging station (though I'd assume most Porsche drivers are rather price insensitive), and/or finance any overproportionate battery degradation for the specific car by using parts of the proceeds for each charging of a specific vehicle to pay for a "battery replacement under warranty".
That reasoning makes Porsche sound so daft, that I thought I better provide the source:
Porsche says ‘Tesla’s Superchargers are not sustainable’, they will charge more for their own charging network