Many good points. I take issue with just one thing.Yes it works but IMHO:
Goes back to the more "steady" anchoring points you have the less "wobble" you will encounter and helps steady the shot. Rock, concrete, wood are good but soft soil, mud, hay bale allow the mag to "dig" thereby lowering the mechanical P.O.A.. The amount you need to physically "readjust" your P..O.A. will vary based on you overall shooting position and skills: might not add anything perceivable or may delay your follow up shot(s).
Good firearm, mag fit and mag you can do it but is there a benefit to what your doing/shooting? Shooting at minute of BG @ 25 yards or XX Ring at 600 yards, slow or rapid fire?
Mags are suppose to be consumables. However, we all want to get the longest use we can from them. Anybody going to practice grinding their non-metal mags on concrete? The high speed folks with mag "booties" installed might. Lol see thepile of stone dust created? Hardest material wins but that does not mean it wins without wear on itself.
Tactically, in no cover: if view of target was unobstructed (keep in mind the reverse view), I would tilt rifle over and get the lowest frontal profile I could fire from. I'm not going to expose 4-6 more inches of my CNS if I can avoid it.