I don't think we are arguing the logic of decision making based on observations, that same logic is not even unique to warfare in general let alone SA. I think the contentious issue is the type of information and the type of decision making required. There is a large swath of information you don't need or particularly care about if isolated in a 1 vs 1 fight. It's not just that the unnecessary information is 1/100th as important as it would be if you were fighting 100 enemy as opposed to just 1 enemy, it's actually of absolutely ZERO significance, therefore has absolutely zero effect on your combat efficiency, it doesn't even need to be considered.
If in a complex engagement however, not only do you need and care about that extra information, but it suddenly becomes the focal point of your attention to varying degrees throughout the engagement. So, all of the decisions you make based upon that extra information, although also a result of observations, are not in the same realm as the purely tactical decision making processes, they differ greatly in terms variability, complexity, and the types of decisions you must make.
As an example, in a complex engagement vigilant active SA requires you always be open minded to breaking off one bandit to switch to another. Not only that but, your information precipitating this decision has to be incredibly accurate as precise timing is hugely important. In an isolated 1 vs 1 encounter, no such information is even gathered, the entire decision making process specifically relating to that type of information and subsequent decisions need not be entertained at all. The entire premise of the engagement is fundamentally based upon different information leading to potentially very different decisions.
????
You basically just said the same thing I did, just in your own words, what "point in fact" are you trying to send in this conversation, as it stands now?
The absolute "Zero" of certain bits of information (yet not all) is no different then saying you have less information to deal with. Your discussing when and where "type's" of SA come in and out of play. It just doesn't work like that. In a combat situation, be it 1v1 or multiple targets, you don't break sight of your target just to have a look around once you enter CQB. As you track your target, you gather info on other objects within sight. Yes, there is an occasional "look over your shoulder". This is where wing tactics come in, since WW2, as you said, there where very few times when you had a 1v1. Even then they did not have the comfort of knowing if they where truly alone with this NME. Wing Tactics however where not a part of this conversation, so moving on.
So in a 1v1, your completely focused on the task at hand, that one fighter, every bit of SA that you once used in a multiple engagement is still in play. Just because your not looking for other cons, or friendlies does not mean any "form" of SA is not used, there is so much more you are still looking for, terrain, the position of the sun, can I use these to my benefit, can my NME. Its all the same.... you simply just have less information.
As far as looking for other cons, i don't know to many fights 1v1 that I have not used just about every view during, this is where your "additional" SA comes from, I am watching the NME go into a low yo-yo behind me, while I am looking back, I take the snap shot of the entire scene, sky, ground, anything I can see, if there is a con there, its added to the "big picture" if not, so be it, all still part of the same deal.
Your trying to break the SA into categories, and to be honest you really can not. SA is so intertwined with each component of Combat its like making a house out of cards. If you remove a card, the house will crumble.
Murder and the rest are trying to explain this to you, yet you seem to want to over analyze the situation, or reinvent it.
Its like working on electricity. A ground is a ground is a ground....
Soo.. I will say it like this... SA is TA is SA, slice it how you want, its still SA (being totally intertwined with EVERYTHING else) when dealing with combat of any type.