90.4 would apply to special permission calls by the AHJ.I do think you are right. I just not sure why you were saying it was a judgement call of the AHJ.
Out of curiousity do you agree that when applying the execption of 110.26(E) the work space height is to the top of the equipment?
Yes. I've seen service upgrades where the panels were installed in 42" crawl spaces. Very ugly.