For a given SurfGF there would be no difference. The advantage of Nitrox is that at moderate depths bottom time is increased usefully over air for the (same) acceptable SurfGF. If pushing air to the limit and surfacing without using the additional time Nitrox affored, then, yes, I guess I would agree. But that is not what people are doing with Nitrox, largely they are using it to extend bottom time vs air. If you surface with either with the same SurfGF then there is no difference except the Nitrox diver got more BT for that same SurfGF and paid more $$ for the Nitrox for that additional time.