To open, I forgot* that the 9.2" guns on the Edward VII weren't identical to those on the Lord Nelson... they were a shorter 47 caliber model that was designed 6 years prior to the 9.2"/L50! In that case, Myrm, shouldn't that mean that the 9.2"/L47 secondaries on the Edward VII class should also be Weak not only due to spotting interference, but this as well?
Possibly - its not based on the gun as both ran at around 2800fps muzzle velocities and had similar ranges. Given that I was assuming the reputation of the guns on different ships - be it mounts, mounting style, fire control and level of wear in specific ships - that made the difference for the statting rather than something inherent in the guns then there'd have to be something similar for the L47 9.2s as their basic physics are not really much different. Wiki at least lists the shell identification issue for KEd VIIs, there's no local control and like the Lord Nelson the two 9.2 turrets on each side were under a single firing group. So it all depends on exactly what it was feature wise that made for the weakness. If it isnt the fire control set up but the amount of firing the guns had done and the propellant buildup causing problems (which it was according to Navweaps) then if the ship has fired less then there are reasons for it not having weak.
Another option is the ammunitino used - 2CRH and 4CRH I think are two of the shells available, and it made a difference what you had in the magazine - also powder level - if one class fired routinely on lower powder due to supply limits per shell then it makes sense as well
THis all might come down to sea stability of the vessels and so its position as a platform in question not the guns....for the 7.5s I simply don't know the guns seems to have the same sort of physics. Again any of the above ideas may be relevant
However I don't know enough to settle on an answer - in all of this I was merely offering possible options, not arguing a final case.