1-A would mean that you are fully transcendent to an infinite or uncountably infinite hierarchy of layers of realities, with each reality trivializing the one below it infinitely. This could be depicted in many ways across fiction, such as
reality > fiction differences or viewing the entirety of the lower reality as the size of an atom, for example. I also want to note that a fictional verse does not need a hierarchy to attain this tier, unless its demonstrated that the character or realm in question is beyond the logical framework of the baseline reality, no matter how many layers of reality that you could stack on top of each other to reach it.
1-A+ would place you an infinite amount of layers of reality above standard 1-A. To simplify, imagine 1-A as
Low 1-C and 1-A+ as
High 1-B. And with this logic, each realm would have to trivialize the lower one into insignificance of course.
High 1-A would mean you are fully transcendent to an infinite or uncountably infinite hierarchy of layers of 1-A realities (or basically a
1-A+ structure), with each reality trivializing the one below it infinitely. This could be depicted in many ways across fiction, such as
reality > fiction differences or viewing the entirety of the lower reality as the size of an atom, for example.
Tier 0 to
High 1-A is what High 1-A is to
1-A. There is no end point to this tier, so you could make a tier 0 superior to another tier 0 simply by proving that the character is superior in the verse