End Area volumes

If your design surface has two existing surfaces at one cross section do you have to run the volume calulations twice, once with each surface? How does this affect fill factors and unsuitable materials. Thanks,

From the help file - "You may have multiple existing, design, or substrata in a given cross section set. However, you must have only one existing surface for any given cross section at a given station in order to compute volumes. If you have more than one design surface in a section, they should not overlap."

IR 08.09.02.16