I don’t believe the verbiage has anything to do. I have all my info filled out, Registration, Trade-In, Payment, Insurance and mine doesn’t say Prepare for Delivery.
Prepare for Delivery literally means finish filling out your items in your checklist. In his case, it’s the Trade-In that’s still being evaluated. Once that’s done, Prepare for Delivery will disappear.
I think it depends on two things: when you submitted your order and if you were a transfer over from an existing Model S order. I don't believe anyone who ordered in the time frame that I did (beginning of Feb) has "prepare for delivery". I believe we all have "March".