Here was my "trade-in" experience.
On Sunday I requested a trade-in value for my previous Model Y. The offered price was OK compared to Carvana, but not great. I next ordered a new Model Y from inventory, applied that trade-in, and took photos of the car from the Tesla app (car is in excellent condition).
On the next day, Monday, the trade-in still showed as pending. But later I got an actual offer which was $2,900 less than what they quoted the day before. I scratched my head trying to understand how the amount changed so much but there is no one at Tesla you can talk to. I did have one minor accident (rear ended and had to replace the cracked plastic facia at the rear) which I reported when I requested the trade-in.
The sad part of this process is that if I refuse the trade-in and cancel my order then I am still out the non-refundable $250 deposit, even though Tesla changed the trade-in offer. I knew they were allowed to do this, but it just seems like a way to bilk customers out of that $250. I know I can sell the car elsewhere, but my reservation for the new car is only good for a few days (ends this Friday) and I won't have time to do that before I lose the $250. Also, my state only taxes the difference between the MSRP of the new car minus the trade-in, so I will lose that tax savings if I sell elsewhere.
Just a heads up on how this works, and it's set up by Tesla to be very much to their advantage. I still don't know of any way to find out why they lowered their trade-in offer by so much. Maybe I could have gotten a final approved trade-in offer before I ordered, but I'm not clear about that?