I completely understand why you would be annoyed, but look at it from Tesla's perspective and that of logistics. If they go by when the order is confirmed, they can start sourcing parts, and forecast builds by model. If they go by deposit date, the queue would be constantly changing. Let's say you wait 6 weeks to confirm. When you confirm, if Tesla tried to "insert" you into the build queue, they could end up in a position where many orders behind you have parts sourced, but yours does not. They would have to skip your order, effectively pushing you back anyway. So then you might suggest: ok, give me the earliest build slot where parts can be lined up. But that creates a domino effect pushing every order behind that slot off by one. It would make it impossible to give people an accurate estimated delivery date. At some point you have to draw the line, and confirmed date is the simplest to implement and the easiest to communicate.