More interesting logistics information (which I'm posting since Amazon has been opaque in regards to its warehousing/logistics in regard to the tricorder).
My updated tracking info on USPS still says "USPS Awaiting Item TUCSON, AZ". But more information has propagated through both USPS and Amazon systems. USPS now indicates that the package was originally picked up by the still unnamed "Shipping Partner" yesterday, July 17th at 2:28 pm. In other words, it had already SHIPPED, and hour and a half BEFORE I spoke with Amazon (when Amazon was still saying only "Pending" and not even "Processing" let alone "Shipped"). In other words, Amazon's own Supervisor-level internal data substantially lags behind Amazon's actual shipping activities.
Amazon's tracking information seemingly confirms this report by USPS, with an UNdated and UNtime-stamped "Package Left the shipper facility" (meaning Amazon doesn't want to identify to the customer WHEN shipping actually began, nor by WHOM exactly). Moreover, an additional update indicates "Package arrived at an Amazon facility. Phoenix, AZ US" at 1100 PST (an hour and a half ago from the time of this post). This means that the Tricorder left a warehouse of some kind somewhere (associated with, but perhaps not belonging to Amazon, because it doesn't say "Package Left the *Amazon* shipper facility") and has gone TO an actual "Amazon" facility, where - presumably - it is either being sorted for pick up by the various different delivery services or is being sorted into different Amazon trucks for delivery to the various delivery services. This still seems to be within the timeframe of Amazon's "plan" the Supervisor imparted to me yesterday that indicated USPS would receive the package around 1500 PST (the time relayed by the Supervisor was more specific - ie provided to a specific minute supposedly - but I don't recall the exact time he gave me). So it will be interesting to see if their planned logistics is actually that accurate.
EDIT: Same day, around 9pm PST. So the package still has not been delivered to USPS by Amazon. Currently, the only update on the package's status is on Amazon's site, which declares: "8:38pm PST: Package left an Amazon facility Phoenix, AZ, US". So much for Amazon's "plan" to have the package in the hands of USPS by today at 3p PST.