Earlier this month it was announced that the U.S. Postal Service was testing out how badly it could screw up the delivery of Amazon Fresh grocery shipments in the San Francisco area. But a recent regulatory filing shows that USPS has hopes of bringing its laid-back, carefree delivery approach to groceries and other items all around the country.

A notice [PDF] filed earlier this week with the Postal Regulatory Commission details the test of “Customized Delivery,” which USPS considers an “experimental product.”

“Customized Delivery is a package delivery service offering that will provide customers with delivery of groceries and other prepackaged goods, primarily during a 3 a.m. to 7 a.m. delivery window,” reads the notice.

Those very-early morning hours are the ones during which USPS trucks are mostly sitting idle, so why not pack them up with stuff and get some use out of the trucks?

According to the notice, an expanded two-year test will begin around Oct. 24 and will not only tell USPS whether or not it can make these deliveries without screwing them up too badly, but will also help determine what USPS should charge the companies hiring it to make these deliveries.

Though the filing doesn’t mention Amazon specifically, there’s little doubt this is the company described in the details of the initial test that is already ongoing.

USPS says that this unnamed retailer deliver groceries to the Postal Service in branded totes between 1:30 a.m. and 2:30 a.m. Each tote will have a QR code on the outside for tracking purposes. The codes are scanned with iPhones at the USPS shipping center, where they are then sorted onto delivery trucks for deliveries over the next few hours.

“These deliveries are unattended — the [carrier] will not ring the doorbell or knock on the door,” reads the filing. “The carrier places the totes in a location designated by the consumer for delivery.”

Customers have been averaging 1-4 totes per delivery, which seems like a lot of groceries to just leave on someone’s doorstep in the middle of the night unattended. In my neighborhood, that would last about 10 minutes before either a passerby or feral animal got to it.

A rep for USPS confirmed to the Seattle Times that the purpose of the filing was to expand Custom Delivery to new cities and to retail customers beyond Amazon.

It makes some sense that Amazon and other retailers would consider turning to USPS as a delivery partner. Both UPS and FedEx have raised rates in recent years while the cash-strapped USPS is in desperate need of some new business model that could save it from complete collapse.

However, USPS thinks it could earn $10 million — at most — a year from the two-year test. That is nothing compared to the nearly $2 billion that USPS lost in the most recent quarter alone. In addition to the huge operating cost of running national mail delivery network, USPS has the added burden of being required to pre-fund a huge retirement benefits plan for its employees.

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