oops, sorry for my earlier confusion. I see ya were referring to the mode channel. P7 didn't have it, and it could use bum files, and maybe normal maps, as P8 could use ddn (normal map) files which were plugged into the gradient bump channel, with the gradient bump mode selected.  apparently selecting the mode was redundant in P8, similar to the way the refract node worked in several channels other than the refract channel.