But again, we have a table from an unknown or uncited source...
http://www.thegunzone.com/glock/kb-notes.html
"“This was first confirmed via a European cartridge maker (Hirtenberger in Austria) from information given to me by a high level Glock representative. 1/10" set back can cause pressures to double from 35,000 psi to 70,000 psi." (The "me" in the quote refers to Walt Rauch.)
So now we're working with a known and cited source.
There is no mention of the type and weight of the powder charge used...
Todd Louis Green's data (Todd has worked for at least two major gun manufacturers that I am aware of and is a certified armorer for at least 5 brands) indicates that the pressure rise can by a factor of 2.76 from 0.1" of setback.
http://greent.com/40Page/ammo/40/180gr.htm
The point is that IF a standard pressure round is set back 0.1" during feeding the pressure can rise to a dangerous level in some loadings of some calibers.
..., or of how a round with a COAL of only 1" would go unnoticed when replaced in the magazine or would feed without jamming... or of how a bullet seated that deep would not bulge the case enough to prevent chambering.
1. It doesn't matter what powder was used or how much, the fact remains that setting back the bullet 0.1" CAN cause the pressure to double. There's a critical difference between "can" and "will". As you determined, it does not ALWAYS cause the pressure to rise dangerously--whether it does or not is dependent on the caliber and upon the loading.
2. Detecting the setback while loading the magazine assumes that the round is unchambered. If the setback occurs during the process of feeding the round into the chamber the shooter will not be able to detect it.
3. It may not feed if the setback is severe. However, that's certainly not a given. I have guns that will feed empty cases from the magazine.
4. It probably won't feed if the cases are bulged in the process of setting back the bullets. However, a few of the rounds from the picture in the OP have at least 0.1" of setback and don't exhibit any bulging or deformation.
Your testing in 9mm is very interesting and the results may be valuable in terms of assessing the risks of setback in 9mm--at least within the parameters of the testing you performed. However given that the testing was narrowly focused, the conclusion should be similarly narrow in scope. If that wasn't immediately obvious, it certainly is now that we have data from an ammunition manufacturer demonstrating that setback can certainly be dangerous in at least one caliber and loading.
By the way, here's at least one source that indicates that setback may even be an issue in some 9mm loadings.
http://www.thegunzone.com/glock/setback.html
"...the truncated cone hollowpoint bullet would ram the feed ramp with enough force to set the bullet back in the case reducing the powder chamber and resulting in much higher chamber pressure for the given load powder.
Some years ago (circa '93-'94) my Agency took Federal Hydra-Shok ammo out of the field for just this sort of problem in our 9 X 19mm S&W and Glock autos. They were blowing out the bottom over the feed ramp.
...I measured each round after it had been hand-cycled, and every single round was shorter. ... When I had fired 25 rounds I took the 25 round left over that had been chambered by the firing cycle and measured them. They were all also shorter, drastically shorter than the hand-cycled rounds."
And here's another indicating that as little as 1mm (0.04") of setback in 9mm can result in a pressure increase of approximately 6KPsi--or approximately 15KPsi per 0.1" of setback. Given that ammunition that is most often rechambered is self-defense ammunition which is typically loaded near max, or potentially over max in the case of +P or +P+ , a 15KPsi increase in pressure could certainly be significant.
http://www.thehighroad.org/showthread.php?t=663075