Its not a full Tax Credit. Its an incentive for trading in your car.
If your location is actually "los angeles" like you say, there is ZERO tax benefit for trading in your car to a dealer anywhere in california. If you recently got here from another state that does that, then maybe that would surprise you. If your not in LA anymore and in another state, it might be the case there...
California is NOT a state that gives any sort of tax credit / money off taxes for trading in a car.
Back to OP post... Thanks for sharing your data point! It seems to me from reading here, that tesla many times gives better than average trade in values for NON tesla cars, and worse than average trade in values for tesla cars.... which is the opposite of a traditional dealer.
Traditional BMW dealership will normally give more on a trade in than a Merc dealership would, on a BMW for example. Not always, but if the car was clean, and they wanted to sell it, having nice used cars for their used car dealership would make them sometimes give a better value.
Tesla doesnt want either used teslas or used non tesla, but seems to put a premium on "getting you into the brand" so to speak.