Here is my own wording on PD9:
"Because the pleasures are of differing lengths in time, and occur spread out through time and in differing parts of the body, this is why they feel different from each other."
Yet I still think that there is an implication that the underlying sensation of pleasure is the same for all types of pleasure inducing stimulus - the only thing that varies is the intensity, the duration, and the part of the body that feels the pleasure.