I ordered in January and took delivery at the end of March. My initial trade in offer was right at the bottom of the range listed on reputable pricing sites. I asked for a higher trade-in, putting my car in the middle of the range, and they agreed.
Twice my offer expired, as it only lasts for 30 days. The first time it expired, I resubmitted my odometer, and they came back at exactly the same as what we had agreed upon. The second time, three days before delivery, they came back $500 higher.
It's true that Tesla is not going to resell this car so they don't really want your trade, but they do want the sale, so if you feel they have given you a price that is too low, talk to your sales advisor and they will likely fix it.