Yeah, I guess some people use the names interchangeably. I agree that it can be useful to look at them separately, which was done in Fehige (1998). Their difference is also described in the following way (on Wikipedia):
[Parfit] claims that on the face of it, it may not be absurd to think that B is better than A. Suppose, then, that B is in fact better than A … . It follows that this revised intuition must hold in subsequent iterations of the original steps. For example, the next iteration would add even more people to B+, and then take the average of the total happiness, resulting in C-. If these steps are repeated over and over, the eventual result will be Z, a massive population with the minimum level of average happiness; this would be a population in which every member is leading a life barely worth living. Parfit claims that it is Z that is the repugnant conclusion.
Yeah, I guess some people use the names interchangeably. I agree that it can be useful to look at them separately, which was done in Fehige (1998). Their difference is also described in the following way (on Wikipedia):