Just like Tesla fulfills orders for Model S and Model X for Europe in the early part of each quarter so they get delivered near the end of the quarter, I'm betting they are trying to fill the pipeline with cars to East coast, then backfill with West coast cars later in the month so the January numbers are as strong as possible. First week - invites to East coast. Second, Third and Fourth weeks to West Coast. A mid-January order in Oregon may be delivered before an early-January East coast order. The market really wants to see consistent growth in production numbers. Staggering things in this way optimizes deliveries by month.