I have not tried using the Overlay Component with the Top set to Follow Surface before. We have a project where the current direction is a milling and resurface to match existing - no corrections or adjustments.
I have created a surface from the corridor that is now supposed to be following existing from one edge of road to the other, using alignments as point controls to make them follow the overlay area exactly. In the Roadway Designer, the components follows the active surface, but when I look at the resulting DTM, it is not the same.
Is this a limitation of the overlay component and is there any way to get a proposed DTM that follows the surface within certain portions of a template and follows standard components for the remainder of the template.