They're formally identical only if you consider the choice to not counterfactually affect the outcome. Asserting that counterfactuals don't go backwards in time makes the choice not affect it, but that's just question begging.
It hasn't been formalized because we don't know how to deal with logical uncertainty fully yet.
If I have the 100% version of the lesion, it is true to say, "If I had decided not to smoke, I would not have had the lesion," because that is the only way I could have decided not to smoke, in the same way that in Newcomb it is true to say, "If I had picked one-box, I would have been a one-boxer," because that is the only way I could have picked one box.
You're given the option to torture everyone in the universe, or inflict a dust speck on everyone in the universe. Either you are the only one in the universe, or there are 3^^^3 perfect copies of you (far enough apart that you will never meet.) In the latter case, all copies of you are chosen, and all make the same choice. (Edit: if they choose specks, each person gets one dust speck. This was not meant to be ambiguous.)
As it happens, a perfect and truthful predictor has declared that you will choose torture iff you are alone.
What do you do?
How does your answer change if the predictor made the copies of you conditional on their prediction?
How does your answer change if, in addition to that, you're told you are the original?