If you go to pick your car up at a delivery center, which was the normal process for most Teslas sold before Covid, you got to inspect the car before signing any paperwork. Therefore you signed paperwork after being given the opportunity to take in the car in its as is state. At least in California that is how it works. You don’t sign any paperwork until seeing the car. Once paperwork is signed the car becomes used (there is a non-dealer registered owner on file) and the value drops so it is in Tesla’s interest to have cars rejected before paperwork is signed so they can get more money as a new car when they have to sell it again.
And if there wasn’t anything wrong with it, they wouldn’t discount it. A $2-3k discount for 150 miles is unheard of unless there is something wrong with it. The discounts are usually equal to what it would cost to repair or replace what is wrong plus a roughly $1 per mile discount. Take mine for example. 1520 miles is $1500 off. I got $2760. Where is the other $1260? If you were to buy a new wheel and 2 tires (so they have equal wear) it would likely come out to $1200 from Tesla. Pretty simple math.
Your $10k discount for 1600 miles is because of the excess stress put on a car In track testing mode. Lots more horizontal stresses on steering and suspension components along with extreme wear and tear on driveline. You got a great deal but the wear on your car is equivalent to over 5,000 regular miles and the car was priced accordingly.