Hmm?
Alright, first, how are they two different things when both of them are usually referred to as the extension of the temporal dimension? What is an infinite multiverse with only 1 time axis, anyway? Unless I'm wrong here, it's impossible for infinite universes that are all causally disconnected by the 5th dimension to share the same time axis. But of course, I might be wrong, maybe you can cite the scientific sources? I'd like to see it, no offense.
Aight.
FAQ : How Temporal Dimensions impact tiering
The timeline part
Things like timelines having time that passes at different rates would not qualify, as even the theory of general relativity already establishes that with just one regular time dimension time can flow at different rates in different places. Time flowing backwards in another universe would also not qualify it to have an additional time dimension, as it would still use the same directions of past and future as regular time, just with events playing out in reverse. For the same reasons, statements about independent time streams or of separate kinds of time, which could flow parallel to the original time, would not qualify.
All these lines imply that for different universes or timelines to have different time dimensions, they must be stated to have so otherwise it's just different rates of flow of time
Similarly, it is the same case with the relationship between a container space-time and the contained space-times[like universes inside a multiverse].
The relationship between the spatial dimensions of a universe and the additional temporal dimension(s) may be visualized as something akin to the frames of a movie placed side-by-side. Basically, the time-like direction may be thought of as a line comprised of uncountably infinite points, each of which is a static "snapshot" of the whole universe at any given moment, with the set of all such events comprising the totality of spacetime.
This structure can then be generalized to any number of dimensions, which is why destroying a spacetime continuum is a greater feat than destroying only the contents of the physical universe (Low 2-C, rather than 3-A or High 3-A).
A spacetime continuum with two time axes, instead of just one, could likewise be visualized as a line comprised of uncountably infinite points, each of which is a static "snapshot" of the entire regular timeline with 3 space and 1 time dimension. It would hence be one level of
qualitative superiority above a timeline and as such baseline Low 1-C. Similarily, adding even more time dimensions would add one level of qualitative superiority each time.
So, if the multiverse as a whole and any of the universes inside really had different axes of time, it would outright fall under this category of Qualitative Superiority, or should I say, Higher Dimensionality, since the prior is currently under discussion to change.
Additionally, if you still have some doubts, you can also check why DBS and DBH have been accepted for Low 1-C cosmology, as it was the first verse to be accepted as L1-C with such reasonings, it will naturally be detailing more stuff as it was not known much at that time.
So yeah, this was also why I asked the question in the first place, as nor timelines and neither multiverse and universes by default have different axes of time, and must be stated to do so. if they do though, they can be tier 1, otherwise they will be the regular old tier 2.
And second, I didn't mean to bring "flow of time" here, as I just said "flow". I brought it up because Gurren Lagann's timeline is actually a multiverse with an infinite-branching path that goes independently from the other multiverses (that branch infinitely too), which CMIIW is relevant to your question except I interpreted it wrong.
I remember reading some stuff related to this on their profiles far ago but I don't remember much of it now, in any case, if these timelines really do have such structure, I see vast potential in it, especially if the "direction" of their flow of time is also different, which
as said in this case, it would be able to qualify for H1-B.
So yeah, if its like that, I feel like Gurren Lagann could go for a revision[?]
And for your real question, if relevant, you can only reach a higher tier than 2-A in such a way if you can prove the "higher time axis" is actually the next temporal dimension, a higher dimension of time.
This has been answered in the previous part of this reply where I linked the FAQ
EDIT : Forgot to say, but if it really
was how according to you time axis are, than mostly every tier 2 would needed to be upgraded to tier 1, because many have things like multiverse containing universes and stuff, instead of just plain out big number of universes without a real container. IIRC the new standards for time axis were implemented on October ~ November of last year, so maybe you weren't aware?