I put in the word "moreso" because I do realize that if it's in there longer, shadows will come out a bit more, but then you'll blow your highlights way out of proportion by overdeveloping. Shadows stop developing first in the developing process and after a point, they are incredibly difficult to budge without blowing out your highlights.
That being said, I'm not sure how the logic of under exposing and over developing can bring out shadow details can be consistent. There would be less density in the shadows in that case.
Actually, it isn't difficult at all. Just slow down your agitation to something like every three or five minutes, and that takes care of not blocking up your highlights. It isn't perfect, but it sure gives me better negatives then if I just extended the developing time.
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh