I forgot about this video and just now watched it. I am very glad to know you were a math major because that means you understand logic. On the other hand, neither of us, nor probably anybody else in this forum, is an expert on perception. I really liked this video because it laid things out clearly and with greater detail when it comes to the "mystery" part. Some reactions:
1. In my video analysis of your first shooting video I was attempting to kind of document what it is you were doing. I was looking for clues as to what might be causing your shot success. Sometimes you think you know what you are doing but in reality you don't. We are all victim to that. I'm not saying that happened here, but the video did disclose a couple of things which may or may not even matter. It's just data at this point. One observation is that you do approach the cue ball with the cue on the same line for each shot, and then pivot or sweep the cue into the shot line. I also observed that you were doing 1/2 tip pivots, but I agree that this isn't really important. What is important or relevant is that you ended up on the correct shot line each time, and that shot line was at a greater and greater angle to your initial cue and body position as you stepped in. Since you were stepping in the same way each time you had to make a greater and greater pivot to the NISL. Let's come back to that below.
2. In your video you moved the balls forward and then at 11:20 you said that you got the AL/SL and then before you got the NISL you said you can already tell the perception looks different than the prior set up. This is confusing. Can you elaborate? For this inside B shot the AL is edge to B (center ob) and the SL center to left edge. If you are consciously trying to align to these two spots and can even confirm while down on the shot that you can still see the AL as edge to B and can still see the SL as center to left edge then how can that alignment appear any different from the prior one?
3. Given item 2 it seems like the mystery is occurring before you acquire the NISL. IF that is true, and I'm not married to that idea yet, then there is a contradiction with your first video. As I mentioned above in item 1, you entered into each shot exactly the same way with the same body orientation and cue alignment and that suggests you were seeing the sight lines the same way. It appeared that the larger and larger shifts to the shot line as you moved down table happened after you were already down on the shot. What I'm getting at is at what point does the perception change? In the first video you entered each shot on the exact same body line and then adjusted to the shot line in shooting position. In the second video you are saying that the AL/SL lines look different before you get down to shoot, which suggests that there won't be much of an adjustment to get to the shot line. I hope that makes some sense.
4. Do you think the NISL adjustment is a fixed angle for all shots? In Stan's 4th video he demonstrates how he learned about stepping the cue ball. He puts a cue ball with red dot facing up and 1.5 diamonds away from the rail diamond. He shows how to avert your eyes to the edge of the cb and that shifts the alignment between the red dot and where it crosses the diamond to the edge of the diamond, or about 1/4 inch from center. I did the math considering that the cb was 12.5" + 6.25" + 3.5" to the diamond, assuming Stan was using his 9 foot table. That means that the gaze at the cb edge shits center ball by 0.64 degrees, or just over a quarter inch for a two diamond separation shot as in our examples. That means the NISL procedure shifts the contact point by maybe half of that depending on how far apart the balls are. I'm not concluding anything about that other than to ask if the NISL is a fixed angle adjustment. Stan, to my knowledge, doesn't say but I do not have the book.
Again, good video.