I checked the history edit on the wiki to get an indication and the Pvkv III has been listed there as -12/+15 vertical guidance since June 2022 (the introduction of the tank). So i assume that this one is unchanged since release.
The Pvkv II however is still listed as -14/+17 (and has been unchanged since April 2020) so the change to -11/+17 must have been recent.
There is way too little discussion about historical values and performances, but the moment something gets nerfed, all the experts crawl out and dig out all the sources 😂
Well of course, players assume the values to be correct so when changed they wonder why and look it up.
To counter your argument though; there are lots of communities and threads about different vehicles and the historical accuracy of them being frequented without the prompt of a change.