Our civil sites consist of areas with different Material depths (i.e. concrete, asphalt, topsoil, riprap, etc.)
Could you add an earthwork calculator that computes the subgrade volume between two surfaces?
The routine would bring up an editor that list all the Parcels for a Site, and has a column where the User can enter the Material Depth for the Parcel. The Material Depth(s) would be subtracted from the top surface (FG) for the volume calc.