I think we are at a point now in 2024 when the code authorities, when using NEC2023, will ALSO need to see a nameplate which agrees with the derated breaker (50A in this case derated to 40A). Currently Tesla ship the WC with a 48A nameplate sticker so even if you commission the unit down to 40A it will still fail inspection. Some EVSE makers have begun shipping one nameplate sticker for each of their 'commisioning levels' so the installer can get the breaker and label to agree. I believe the logic here is that when you sell the house, and the EVSE is a fixture and fitting, the the next owner (more likely their home inspector) can see that the WC is derated to 40A and NOT safe to turn up to 48A in a re-commisioning.
