First off, the pay-per-use model introduced earlier this year with 400 kWh in free Supercharger credit per year is still the default model for accessing the Supercharger network for all new vehicles being purchased today onward.
For owners with vehicles ordered before January 15, 2017, nothing changes and they are still on the original Supercharger access program with free Supercharger for the life of the vehicle.
What changes for vehicles ordered after January 15, 2017, is that they are now not only off of the paid model with 400 kWh in free Supercharger credit per year, but they have now free Supercharging access for the life of their Tesla Model S or Model X ownership – meaning that unlike the original free Supercharger access model, the free access is associated with the owner instead of the vehicle.
In other words, a Tesla Model S or X owner who bought a new car since January 15, 2017, has free Supercharger access now and for any other Model S or X (not Model 3) that they decide to buy in the future. If they do decide to upgrade in the future, their current vehicle wouldn’t have free Supercharger access for the new owner.
It’s a way for Tesla to maintain the free access program while making sure that it doesn’t become unsustainable due to the growing pre-owned Tesla fleet.
Pre-owned vehicles produced before January 15, 2017, are still listed with “free Supercharging” and can be purchased right now, but future used Tesla vehicles will not have this advantage even if the original owners will actually have had access to Superchargers for free.
So that covers all current owners. They either fall under the category of the original free Supercharger access associated with the vehicle or the new updated free Supercharger access associated with the owner instead of the vehicle.
As for new owners purchasing a new vehicle now and who haven’t purchased a Tesla sinceJanuary 15, 2017, the default model is the pay-per-use model with 400 kWh in free Supercharger credit per year as previously mentioned, but Tesla also updated the referral programs to include free access to the Supercharger network under the model associated with the owner instead of the vehicle.
Therefore, as long as new Model S or X buyers use a referral code, they can still get free Supercharging (on top of the usual $1,000 referral discount).
I hope this clarifies the situation.