It's GRAVTITATIONAL time dilation, not anisotropic-universe time dilation.
Very true, I am. I assuemd that since Dr Humphreys big assumption is that the matter in the universe is unbounded(no voids in space, all space is completely filled with matter) then the path of the light reaching us would be affected by the medium in which it travels(local "GRAVTITATIONAL time dilation" along it's path).