How and when M-B vehicles (and maybe other marques as well) are shipped is shrouded in mystery. I waited five months for my CLA 45 to be built, and I was notified by my sales rep. He then told me he would let me know when the car arrived in the US. Then as if by magic (and only a week or so later), not only had the vehicle arrived on the US shore, but was on a truck headed for the dealership. I got the email from the dealer saying, "Oh, by the way, your car will be here Friday." What? 10 days ago it was still in Europe! OK, super!
I agree that it would make much more sense to deliver the customer-ordered cars first. But, I imagine that they get loaded up on trucks by dealer location, truck routes and probably a dozen other variables. As long as you know it's on the way...