well, perhaps at a certain level of realization there isnt a difference ... but im speaking from the perspective of a "dualistic self" here, so bear with me ...

dissolution of "object center" is pretty unremarkable. would be like magnifying a tiny particle, say an atom, and discovering that when you look close enough its really just empty space in the middle. dissolution of "subject center" is more elusive i think, but it entails an aspect of self-reference (or maybe "observer awareness" would be a better term). like events are unfolding, and each event is being observed, but its just a process and you cant really discern an observer or even a "point of view" from which the observation is taking place.
in my experience, the former is simply a product of attention ... if you look/listen long and hard enough, you can "see the space between the lines"/"hear the gaps between the notes". but the latter is tricky and the observation process much more elusive (having something to do with self-reference or awareness of awareness). and perhaps they lead to one another at a sufficient depth (my few brief encounters with the latter have been by way of the former), but i think you can definitely have object dissolution without dissolving the sense of self.
am i making any sense here?