I've said that manuscripts are phrasebooks to the complicated language that is fencing. As you read the manuscripts they're all quite "You are here" "You do this" which is nice. But it doesn't really cover the whys and wheres. So often you'll end up out from the play you had in mind and unable to perform it.
This is the main reason drills fail- even Cooperation you can't guarantee you'll fall in the right space.
You read and converse through body language and the tactile feedback of the blade. Listening to that is where you succeed- nudging the forces to an optimum solution, not overcoming it with force and stubborn idiocy.
So you have "ish" and "thingummy" and "doobrie" and all the weirdness that comes with being a proper language rather than the call and response of: "where is the swimming pool" "Down the road, third turning on the left"
You might be at the cross somewhere between "pommel strike" and "cut over" a whole load of context will tell you which is correct. Your oppo being more prone to retreating means the cut is probably going to be more effective. You get to know why the sword equivalent of "red big balloon" is wrong, despite it having the correct components.
This means that all the IF/THEN statements are woolier than the text suggests and there's no absolutism in the interpretations. After all no skill/speed or stature is truly matched so everything is to be adapted to the moment. Something that can't be done if you have subscribed to the phrase-book model
True Guards are a concept that appears in all sorts of places and they can work as a good base for comparative study