Mine is 20 days as well, in SoCal. I wonder if region has something to play, being in LA means a car can be shipped real quick - maybe the car is "tagged" in multiple potential batches?
FWIW, my newest update (Black/Black, 21" RN1149 SoCal):
Aug 10: Nov 01 - 21
Aug 11: Nov 02 - 22
Aug 12: Nov...