I did try to make the structure of my argument compatible with a partial order; but you're right--if you take an atomic preference to be something like "a marginal acorn" or "this girl's number" instead of "the agent's entire utility function;" we'll need tuples.

As far as temporal changes go, we're either considering you an agent who bargains with Kawoomba-tomorrow for well-restedness vs. staying on the internet long into the night--in which case there are no temporal changes--or we're considering an agent to be the same over the entire span of its personhood, in which case it has a total getting-goals-accomplished rank; even if you can't be certain what that rank is until it terminates.