What I'm talking about is that this dimensionless being, or any in this range, really, *could* potentially have some sort of physicality. Not a 3-D property. 3-D physical mass is irrelevant to this grey area. Mass exists in higher dimensions, and could possibly even beyond them, if physics exist regardless of dimension. Additionally, just because a character doesn't have spatio-temporal dimensions doesn't mean that different physics couldn't apply.
About the line of text, what I was saying, and all I've been saying, is that maybe a single line could be added or clarified in the High 1-B area wherein even if a character surpasses dimensions entirely, that if they are still within some framework of physics or mathematical comprehension, or are not beyond conceptualization entirely, that they cannot qualify for 1-A due to not being beyond scientific definition or physics. (Of course, probably less verbose...I would hope you wouldn't use my definition!) This goes with what you are saying with "qualitative superiority".
Regarding the last part, the Chaos Gods / God Emperor of Mankind. This is the text regarding Slaanesh's rating, for instance (whom all these characters [Chaos Gods, GeOM, I mean] are equal or equivalent to: "Hyperverse level, possibly higher (Transcendent of the material universe, which contains a myriad of higher dimensions so great that they 'cannot be defined by so limited a thing as human language'. Unbound by the restrictions of physical reality, such as form and its dimensions, save any it choose to impose on itself and its surroundings.")
(Edit: After looking at other profiles and reading some more, basically, you could rationalize it like this: Even a spatio-temporally dimensionless being could still be considered High 1-B if they are above time and space as a whole at an infinite level, but they are still bound by other physical "dimensions," or properties which keep them in a framework of physics and thus possessing physical, scientifically definable attributes.)