> According to The Film Developing Cookbook, less frantic agitation can also improve tonal scale.(posted 8539 days ago)That makes no sense; too bad neither of those guys participate in these forums so they can be asked exactly what they meant to say.
Modern films routinely provide a very straight curve shape (if that's what's desired) from the speed point all the way out to five or six stops more range than anyone could ever hope to print on silver paper whether intermittent or constant agitation is given.
If that's not what's desired, modification of the curve shape can often be achieved by using different developers and this can be done with constant agitation as well as with intermittent agitation.
See _Controls in Black and White Photography_ by Dr. Richard J. Henry for more than you ever wanted to know about the effects...or lack of effects...of different methods of agitation.