This is not a real point of disagreement.

IMO, in this context, "good" just means "favoured by this moral system". An action that "should" be performed is just one that would be morally obligatory - according to the specified moral system. Both terms are relative to a set of moral standards.

I was talking as though a paperclip maximiser would have morals that reflected their values. You were apparently assuming the opposite. Which perspective is better would depend on which particular paperclip maximiser was being examined.

Personally, I think there are often good reasons for morals and values being in tune with one another.