Thanks for thank Eugenios. This is probably also what is covered in DeWitt's "unity of pleasure" discussions, but I find the entire discussion by virtually everyone to be unsatisfying.
As that wiki entry points out, there really is even lingering doubt as to whether the point is that pleasures cannot be so condensed, or is in fact a hypothetical asking us to imagine that they can be condensed and therefore asking us to think about what that tells us about the particular pleasures.
I could read that to mean that he is saying that pleasures differ ONLY in "intensity," and that he is arguing that the pleasure of cutting your fingernails differs from the pleasure of listening to a symphony only in "intensity" -- which apparently is a way of looking at how much of the total experience of the organism is taken up by that particular experience.
If that were the point, then this would be another way of emphasizing that there is simply no "outside" standard (outside of pleasure itself) by which to judge or rank pleasures. And that would be consistent I think with the thrust of several other positions Epicurus seems to take.
It would also join up with what I think is going on in PD3 and much of the rest of the "limit" analysis, which I think involves looking at life as the "sum total of experience" and thinking about how individual pleasures and pains are added to the vessel to come up with the sum of whatever is in the vessel at a particular moment.
However the point the wiki derives seems to be 'his belief that the various pleasures are in an important sense independent' which would be a very different point, if true.
Eugenios and others - what do you think? Is the emphasis that "the various pleasures are 'independent'" or something else?
I think I end up as usual thinking that dewitt is correct with a "unity of pleasure" approach, but i have not read that section recently enough to recall if I am remembering it correctly.