I'm not sure what you mean here, but the F90X does have 1/3 stop adjustment to the shutter speed, exposure compensation is in 1/3 and even the Program shift is in 1/3. The exposure graphic on the viewfinder only shows 1 stop either way, but in 1/3. BTW, exposure compensation is up to +- 5 stops!
Quite right. I was refering to the argument re. the Aperture increments. Ofcource you have 1/3 stop exposure accuracy just by using the shutterspeed dial. Didn't think it through there, sorry.