is there any sort of method to the act structure at all at this point? like is there a difference between the relevancy/significance of an act, a sub-act (like the second "act" in the act), a sub-sub-act, and an intermission?
Basically intermissions are a drastic shift from one part of the story to a very different part of the story. Sub-acts are essentially just a result of intermissions placed in the middle of an act rather than before or after one however this is only true of Act 6 sub-acts as Act 5 Act 1 acted more like an intermission. And an Act is just an overall section of the story usually each having their own beginning, middle and end.