I suppose you mean the Moon then? Because unless something happens in Chapter 35 then the Herrscher of Finality was always tied to the Moon rather than Venus. And if it is what I think it is, than it's because that is the Cocoon of the Finality, basically the "Egg" that contains the Herrscher herself. Until civilization reaches a certain point in it's evolution it can't hatch, which is probably what you mean by "she couldn't leave it".
Also, not being able to leave something doesn't correlate to AP, so I still don't see the point.
Why, though? It's stated quite clearly in the Alien Key that higher dimensions sees lower ones as nothing more than a book that they can easily destroy, and anyone in it is a fictional character in a story, which is a pretty clear cut qualitative superiority.
Some stuff like Dimensional Travel or Spatial Manipulation.
Though, to answer the actual question, the High 1-B scaling is probably due a statement that the dimensions of space can be Infinite, which can be interpreted in that way. While the 1-A scaling is probably because of a statement that places the Imaginary Tree as "infinite in a transfinite scale", with transfinite cardinals being Aleph numbers, which would be 1-A upwards.
I personally agree with the 1-A scaling for the Imaginary Tree, if you ask me, but I will never make a revision of that for a multitude of reasons.