The Acros diffuse RMS granularity value of 7 is based on development in undiluted Microfine, which is equivalent to Perceptol or Microdol-X. An older Fuji handbook also supplied the granularity value for Acros when developed in Fujidol-E (similar to Xtol), in which case it rose to 7.5.
Kodak's measurements are based on development in straight D76. I've found that 100TMax is slightly (I emphasize 'slightly'), but definitely, finer grained in Fujidol-E than in D76. Perhaps even lowering it to 7.5.
The point is, while Fuji's claim of a diffused RMS granularity value of 7 appears much better than 100TMax's 8, actually there is little or no difference between them. In terms of grain.
However, in terms of perceived sharpness (not resolution), many people seem to find that Acros 'looks' sharper, has more edge to it. I am one of them. Both provide equal detail, yet that same detail seems to pop in Acros, and in 100Tmax it seems submerged, softer edged.
I have never seen any MTF charts for Acros.