So, not that I really want to step into all of this controversy--and the decision has been made already--but out of curiosity, I searched and found an explanation directly from James Brown, lead designer, on another site (link included for verification purposes):
"Back to the discussion on how the Presence works on an EVH 100W.... the choice of using an Audio taper pot on the Presence of the 5150's goes back to my first one......it wasn't anything to do with 'tolerance' or price, just that we already had a 10KA in house and once I put it in the first prototype, I couldn't change it....even though it doesn't really do anything until you get to about 1:00. Ed liked the amp like it was, so I never changed it on any of the Peavey's, and EVH brand kept it that way on the 100W amps.
"When I got to EVH in 2019, I started this Iconic project using the 50W 5150 III as the go-to amp, because it was more popular than the 100W ones. It was also a newer design. It turns out that the 50W's presence had been changed to a Reverse Audio pot, which makes the presence control adjust more 'linearly' across the knob. It's due to how Presence is wired, so it literally changes linearly by using a Reverse Audio(comes up really fast). I didn't even really look at that detail on the 100W amps, but they were still Audio for whatever reason. The funny thing is that so far I've seen NOBODY compare the Iconic to the 50W 5150 III, or they'd find the presence matches pretty closely. Instead they all compare the Iconic Presence that 'comes up fast' to the 100W amps where the Presence 'comes up very slow'. You basically have to keep the Presence down around 10:00 to be where 1:00 is on the 100W heads!"
https://www.sevenstring.org/threads/5150-iconic-new-budget-5150-from-evh-gear.344895/post-5363530
And another, slightly different, regarding the Presence pot taper on the Iconic:
"Now one thing a lot of people have difficulty with is that we used the same potentiometer(electro-mechanical part behind the knob) tapers for the Presence that are on the 50W 5150 III......which is a reverse audio that comes up faster but spreads the control over the whole knob. When I did the original 5150, I didn't have a pot to do that in stock and used an audio, so it's slow to increase and didn't do anything until about 1:00. This 'error' carried on throughout the 5150's all the way up until the 50W III. So compared to most of the other 5150's, you have to turn that knob down lower than you're used to. That can make it sound harsh if you're using a brighter speaker like a V30, but it works great with the Greenbacks and EVH Celestion. So it's one of those trade-offs we deal with all the time."
https://www.thegearpage.net/board/index.php?threads/evh-5150-iconic.2269504/post-34492462
Make of that what you will.
