Digital BW, The Print

this is a very dumb question I am sure, but I have been digital for a long time and never seriously used film.  When I was a kid we had a darkroom at the house but only printed 4x6. I do not remember the size of the grain at various ISO's. I just started getting into film with a nice rangefinder and am surprised that ISO 400 has less resolving power that ISO 200. Is that correct? I did not think there would that big of a diference. I am scanning at 3200 DPI which works great at ISO 200 but everyting is much softer at ISO 400. Is that normal? Thanks putting up with me...Doug M