(I'm one of the Pack & Ship engineers)
I don't think we put out a comm but I'm not 100% sure. I'm pretty certain there will be an in-app comm once you get it though. We've been going really slowly with it to work out the kinks.
Anyway the way it works is that as soon as you scan the shipping label, it kicks you into Sort with that one already pre-scanned. Once you sort it, you're kicked back to Pack and see the next container on the cart. You can enable and disable this yourself, too. So if it doesn't work for your store's workflow, then you don't need to use it.