Another day with little to no West Coast activity.
I assume this is happening because the density of orders is quite high, but the allotments are more similar per distribution center. It would be an interesting experiment to change an order to "Middle of Nowhere, USA where orders are less dense and then re-route the package.
I personally think Apple has handled the logistics of order priority quite well
Chances are the order in which these are being fulfilled in terms of delivery time has more to do with Financial Institutions and UPS than apple. Typically fulfillment would look something like this: Apple receives order, Item becomes available, Apple requests funds from Financial Institution, Apple Receives approval for amount, Apple fulfills order, UPS Picks up, UPS delivers to distribution center with allotments that are rounded to a pre-determind bulk size, those units are shipped to the distribution center where they are broken down (and shipped to smaller distribution centers in some cases) and ultimately delivered. Considering the above, Apple is at the mercy of how long it takes the Financial Institution to approve the transaction as well as how and when the financial institution is willing to take transactions from Apple. Then Apple is subject to UPSs interpretation of the best way to fulfill hundreds of thousands of units through their destination. UPSs logistic regarding Zones and efficiency are pretty insane (e.g. Their aversion to left hand turns on routes).