My apologies for not doing this sooner, but I should probably explain the backstory/context to this. We are a secondary school in the UK, and iTALC is classroom monitoring software. When I talk about configuring iTALC, I am talking about the relevant registry keys that set the authenticated users (all staff). iTALC Master is the actual viewer that sits on the teacher PC in each computer room, allowing the teacher to view the student's screen.
The registry keys have to be applied to all machines, whether they are a master (this sets who can log in to the software), or a student pc (this sets who can see the screen). So all the machines would have the registry configured but not all would have the master application installed. Obviously, all of the machines would at least have the very basic level of iTALC installed.
Not all machines have the master application installed or are even configured need to have the things on there, this is extra PCs like our Digital Signage PCs have the slave installed, also those in my department have the master installed. Though these two examples are nice to know they're there, it's not something that I'm going to worry about if it's not there.
As for the not ready for service collection, that is a collection that feeds back on lots of other collections that report on computers that don't have required things configured.installed (e.g. wrong driver for WoL), if I see a PC in the not ready for service collection, I can then drill down into the subcollections below, and work out what is wrong, without having to search around the whole of my PDQ console.