Sorry, by "delta" I meant change, difference, or adjustment.

The reason to investigate evolutionarily stable strategies is to look at the space of workable, self-consistent, winningish strategies. I know my utility function is pretty irrational - even insane. For example, I (try to) change my explicit values when I hear sufficiently strong arguments against my current explicit values. Explaining that is possible for a utilitarian, but it takes some gymnastics, and the upshot of the gymnastics is that utility functions become horrendously complicated and therefore mostly useless.

My bet is that there isn't actually much room for choice in the space of workable, self-consistent, winningish strategies. That will force most of the consequentialists, whether they ultimately care about particular genes or memes, paperclips or brass copper kettles, to act identically with respect to these puzzles, in order to survive and reproduce to steer the world toward their various goals.