I was a bit confused when I heard Bhikkhu Bodhi talk about this sutta in his MN series. He said the following re the way volitions accumulate: "This accumulation of mental energy, habit energy, volitional energy - this accumulation of energy - becomes a tremendous force, which at the time of death projects the stream of consciousness into a new realm of being, a new realm of existence in conformity with the ethical quality of the volitions themselves."
So in the sutta we have the Buddha telling the ascetic that if one lives as a dog, one will be reborn as a dog - the general accumulation of volition has a say. And I think this is comforting to those of us who place a lot of emphasis on watching our behaviour, behaving in a morally wholesome way in the hope of a favourable rebirth. (It seems to me that many suttas addressed to and/or concerning householders have such an emphasis.)
But having discussed from an Abhidhamma point of view with some people, it sounds like it could be any one citta that decides rebirth, from the present or any past life, and that to place hopes on the accumulated habit energy of volition bearing favourable fruit would be naive. At least this is what I have heard some people say...
Does the way I have described Bhikkhu Bodhi's comments sound technically incorrect at all, or, on the other hand, would it be technically incorrect to suggest that the general accumulated habit energy is *not* likely to have an impact at rebirth? It sounds to me that Bhikkhu Bodhi's comments are (naturally enough!) consistent with the sutta.
Kammalakkhano , bhikkhave, bālo, kammalakkhano pandito, apadānasobhanī paññāti
(The fool is characterized by his/her actions/the wise one is characterized by his/her actions/Wisdom shines forth in behaviour.)
(AN 3.2 Lakkhana Sutta)