Cross-Post
I did some EDD math for those in my area (Seattle). After scouring many posts about EDD's, I've concluded the following for Seattle/Renton/Bellevue deliveries...
On the day ("X") you get the 13-14 day EDD range, that seems to equal the "birth date" of your car (which you can confirm after delivery). About 7-8 days later ("Y"), you will see a VIN (your EDD range will be about 7 days at this point). Delivery date("Z") is about 5-6 days later (Transportation and DC prep). Going the other way, the later date ("Z'") on the range provided on day "X" is about 3-4 days later than when you will actually take delivery on day "Z".
So, it's X+12=Z, or
Z'-3(or 4)=Z
For those in the Seattle area, post your experiences!