So what I'm getting is that the sub-conclusion or intermediate conclusion is basically just a conclusion sentence that provides support for the main conclusion. Such as in Premise 3, it receives support from P1 and P2, P4 however, does get support from P1 and 2 but is not attempting to conclude anything since the main subject is Fluffers. That's why P4 is not considered a sub-conclusion since P5 (the main conclusion) is that Fluffers is cute. P4 needs the support from P3 in order to reach the logical conclusion that; Since all dogs are adorable, and fluffers is a dog. It makes sense that Fluffers is adorable (sub-conclusion). Then, since all adorable things are cute, Fluffers also must be cute (main conclusion). Maybe this was a really roundabout way of explaining it, but thats how I understood it.