Yes, now I see what is wrong with scenario 1. Both Alice and Bobs contribution of 1000 are necessary conditions but neither of them is alone sufficient to elicit utility of 15. Hence neither of their contribution of 1000 alone elicits contribution of 15. Those are only in conjunction sufficient. Counterfactuals are still conditionals and you have to get the logic right.

I don’t understand how both Alice and Bobs utility contribution in the counterfactual could be 15 in scenario 1. Counterfactuals are still based on logic and maths and that does not add up.

Yes, now I see what is wrong with scenario 1. Both Alice and Bobs contribution of 1000 are necessary conditions but neither of them is alone sufficient to elicit utility of 15. Hence neither of their contribution of 1000 alone elicits contribution of 15. Those are only in conjunction sufficient. Counterfactuals are still conditionals and you have to get the logic right.