Shadows are an issue anytime you don't expose for them adequately, regardless of the film/dev combination. In the abscense of any established testing regime, if you are consistently getting unsatisfactory shadows at 400, then bump the EI down a bit, see what happens, you may have to reduce development some to keep highlights controlled.
Originally Posted by GarageBoy
With that said, a shadow value in the toe region of an upswept curve will have a lower density than at the same location with very straightline curve----the straightline curve even lower than a more concave curve as seen with TG7----compare the density values in the toe at Zone III, for example, and even on up the rest of the scale to the "normal" development calibration density at VIII to VIII 1/2. The curves show how different gray scales would be produced with each curve.