OK, let me see if I am smart enough to explain this to you, so you understand. I am not smart enough to use all the goobly gook technical terms, so I will do the best I can in my dummy wordage.
In your quote, it says that the average tidal volume (amount of air you suck in) is 1/2 liter. I SO disagree with that! If you take deep breaths, you will FAR surpass that 1/2 liter mark! I think it is between 2 1/2 to 3 1/2 liter tidal flow. (It obviously varies from person to person.)
The 1/2 liter tidal flow MAY be correct, if you were quietly sitting in your recliner, and just slowly inhaling and exhaling. But how many of us can do that in the midst of a battle with the beast? When I was using the 15 LPM with the standard non-rebreathing mask, I could empty that bag without even trying. If you watch my hit, on YouTube (Watch it here: Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

), you will see my bag is empty, a LOT! It is difficult to see, clearly, between my bouncing around and Luke trying to keep me from pulling my hair and banging my head, but it is there. Near the end, it is easier to see, and you can even see me putzing with the bag, to try to see if there is a kink in the bag, or some other thing wrong.
This empty bag situation can then lead to frustration and even panic. We need to try to stay as calm as possible during a hit, to prevent the escalation of the pain. We have enough pain, as it is, without something contributing to more pain.
What we are doing, when we use oxygen to abort, is causing vassal constriction (shrinkage). A higher level of oxygen in your blood stream, is a vassal constrictor. Carbon dioxide (CO
2) is a vassal dilator (expander). When you have vassal dilation, it puts pressure on the trigeminal nerve, that comes directly from your hypothalamus, which is deep in your brain, at the top of your spinal column. At one point, the blood vessel almost completely wraps around the trigeminal nerve. So with vassal dilation, it puts pressure on that nerve, which leads to your face and eye, causing the extreme pain we feel. Therefore, we need to constrict this blood vessel to remove the pressure from the trigeminal nerve.
In order to do that, we need to increase the oxygen levels, and decrease the CO
2 levels. By breathing the 100% oxygen, we help this along. Normal room air contains only about 21% oxygen, and most of the rest is nitrogen. We need to take FULL and DEEP breaths, to make sure that the only gas in your lungs is oxygen, then we need to exhale fully and completely so that all CO
2 is expelled. Hyperventilating on pure oxygen forces our body to almost stop producing the CO
2 (which, for our purposes, is good), and fills our system with pure oxygen. By doing this, many times, you can abort a mid level hit (KIP5-7) in as little as three minutes.
This process of deep breathing and especially hyperventilating is just not possible with the normal bag that comes with the standard non-rebreather mask, and the 15LPM flow rate. Using a 3 liter bag, and the 25LPM regulator, you do NOT run into the "empty bag syndrome" as easily, and can abort much faster, and efficiently.
Did my long winded explanation help at all?
If not, let me know, and ask more questions, and I will do my best to answer them.
Chuck, the oxygen junkie