Pleasure and pain are like opposite ends of a rope on a pulley: as one goes up, the other goes down. There is no neutral state.
Every analogy has its issues but yes I like that too, especially if you can fix your attention on the ropes hanging parallel with each other and not worry about the point at which the rope is at the very "top" of the pulley and going neither up nor down.
Just like the analogies with the balance scales, where the sides are exactly balanced and you have to deal with how to label the pointer (or the balance) being precisely even.
This is where I think you have to go back to being clear about your perspective. From the "whole person" perspective I would say that discrete pains and pleasures can "balance each other out" where it's hard to say which of the two is greater. But from the perspective of placing weights representing pleasure on one side, and weights representing pain on the other, you're always measuring discrete feelings.
The pointer of the dial may indicate dead zero in sum, but what you're measuring is always an accumulation of (1) discrete feelings of pleasure against (2) discrete feelings of pain, and you're never placing on the scale "neithers" or "something else" or "neutrals" or "mixeds."