A question is "why is absence of pain throughout the organism (macro) the limit of magnitude, whereas a more localized pleasure (micro) can increase beyond mere absence of pain?"
I think we could reword that this way:
A question is "why is absence of pain (which is the definition of pleasure) through the organism (at macro level) the limit of magnitude, whereas a more localized pleasure (at the micro level) can increase?"
If that is saying the same thing, which I think it is, the answer is pretty obvious: a macro level pleasure cannot increase by definition. because it has no more room to increase, while pleasure at any smaller degree than macro level can increase because it still has room to increase.
I am not sure this is any more difficult than remembering "positive, comparative, superlative" as parts of speech.
In "good, better, best" the "good" gives you a description of what you are talking about, the "better" is the comparative form distinguishing one from another, and the "best" is by definition the superlative form which you are saying cannot (again by definition) increase.
I am thinking words like "full" and "complete" and "pure" and "godlike" are meant as superlatives and simply being used to refer to the "best" possible.
And I think these issues we're discussing are the primary and important big picture items to get clear first.
Secondarily we have the kinetic/katastematic issue as Don has interjected I think correctly as "types" or categories of pleasure that are included in the sweeping mix as descriptions that involve manner of experience. As differences involving manner of experience those are useful to consider but i don't see them as words expressing comparatives or superlatives of Pleasure as the general category. You can use and need both. They are types of pleasure like mental vs bodily or hearing vs seeing or long-lasting vs short, but I don't see them as being evaluated as better or best types of Pleasure, which is the big complaint I have against the usual K/K analysis. I would say both are "good" types of pleasure (all types of pleasure being "good") but their relative contribution toward one's total experience can increase and decrease with circumstances as part of making up the total organism over its lifetime. Many types of trees can make up a forest, but what we want to talk about in general terms as a way of evaluating the best way of life (the way we want to set as our goal) is the "forest" level. If we expend our entire conversation on "what about elms?" and "what about poplars?" and "what about oaks?" and "what about pines?" etc etc then we lose our focus on discussing "what about the forest as a whole?"