Aid dollars as evidence of Darfur advocacy success?

Okay, here we go with Q#2. Again, feel free to bite off just one segment of it and/or comment on better ways to construct the question:

A graph in Fighting for Darfur shows that between 2005-2008, Darfur – just one region of Sudan – received tenfold more funding from the U.S. Congress than the entirety of D.R. Congo, despite the latter having a significantly larger displaced population. What conclusion do you draw from the funding difference? Is this evidence of the effectiveness of a mass movement approach? What other factors could account for the disparity? To the extent you do attribute the disparity to the mass movement, do you have ethical concerns about applying the mass movement model to some situations and not others?