In theory - i.e. by making measurements, this may well be true. Looking at prints, I find any differences quite trivial, to the extent it's a matter of taste. My comparisons are on IGFS, where the DMax is already very high without ABW. Maybe the effect would be more noticeable with matte papers if the ABW can eek a little more DMax out of them. When I last examined this for my 4900 review article, I in fact slightly preferred the B&W tonality of the one I did in Photoshop over the oneusing the ABW driver, but both of them were very good prints from a tonal perspective if you looked at each of them individually. In any event I don't like the AWB workflow and didn't see the value-added persevering with it.