Just stumbled across this thread. Purchased my 2022 M3P in December, and requested that the delivery team at the PDX Macadam service center submit the registration with the transfer of my existing plates (not a Tesla trade in, btw). They seemed unsure if Oregon DMV would allow a new vehicle registration with transfer of existing plates, so charged me the full amount and then told me DMV would refund the cost difference if the transferred plates were accepted. Once I received my registration from DMV, I called to request my refund, but they told me Tesla only submitted payment for the transferred plates and I'd need to seek the refund from Tesla. Called Tesla customer service and they issued me a $800-ish refund check without any hassles at all.