I'm working on a roadway project where the existing road is partially constructed in a piece-meal way and so there's alot of "begin construction", "end construction". Because of that, I have many corridor regions set up with different assemblies assigned to them. This is the first time I've tried calculating earthwork quantities with Civil 3D. I want to use an average end area calculation. My question is: Does the program calc volumes by using the stationing of the corridor region, or by using the areas of the actual sections? Or, to put it a different way: Do I need an extra section view whenever I'm changing assemblies?