A Brief History of the SCAN Form
Since I mentioned this in “Refunding Unused Labels Just Got Easier”, let me expand a bit on the SCAN form. We invented this process nearly a decade ago to solve a big problem you merchants/shippers were encountering. Back in the day, USPS had only a delivery event -- a carrier scan when the package was physically given to the recipient. There were no operational "in-transit" scans and that's why the USPS didn't use the term "tracking" back then.
Furthermore, USPS pricing didn't allow for the acceptance scans of each and every package a shipper handed over to the USPS. So what you ended up with after a shipping day was a notice on USPS.COM that said something like this for every package in your shipment:
“The shipper has electronically notified the USPS that a package is ready for pickup...”
And this vague message would stay posted on USPS.COM for 2 or 3 days -- until the actual delivery happened. Your customers were confused by this when they looked up their tracking number -- they wondered if you really gave the package to the USPS and if it was really on its way.
So we adapted/simplified a complex protocol used by a few big shippers called manifesting and made a version that worked within the PC postage world. We did this by segregating tracking barcode numbers generated by each of you, and uploading these records in individual customized batches. We did this batching and uploading based on a request from you -- you can make that request on our Web site, through our API, or directly through many of our clients. That process ends up giving you a single 8 x 11" sheet with a big barcode. The carrier scans that big barcode when he collects your packages. When the carrier's scan co-mingles with the data we uploaded for you, then you get a nice crisp message on USPS.COM for all your packages:
“The USPS has picked up this package at 4:53 PM on 9/30/2013 at ZIP 94306”.
Bam!! Now your package recipient knows you did your job -- you clearly shipped their package!
USPS took a few years to update their own systems (like Click and Ship) to replicate this protocol. And as time went on, USPS began to value this process as a way to “start the clock” on their delivery performance measurements. So now you will see USPS reps and Postmasters encouraging customers to create an end-day SCAN form.
The irony here is that USPS is a bit behind the curve in their thinking on this topic. With the massive improvements made to package visibility, you (and they) are more or less guaranteed a live operational scan on the same day as you induct your package. That will happen either at your local Post Office or the USPS district plant that processes your package that evening. So if you don't create the SCAN form at the end of the day, that vague message I mentioned earlier might only be there for a few hours -- replaced as soon as the Post Office or plant scan happens that evening.
So, my advice is to create the end-day SCAN form if a) it makes you happy or b) it makes your USPS rep or local Postmaster happy BUT realize that it will have little impact on your customers' perceptions of your shipping diligence.