I'm trying to create a subgrade grading surface for our machine controller and SCS900 using the identify site regions command to offset the finished surface down per the paving thicknesses specified in the plans. However, in some areas where a 5" paving thickness is bounded by a 6" paving thickness (or other thicknesses), there are asymptotes at the region perimeter. The surface slicer shows the correct subgrade thickness on one side, then a sharp rise up to finished grade elevation, then back down to subgrade on the other side. The entire peak is only 0.003' wide from base to base. There are other locations on the site almost exactly the same where the subgrade model rises 1" from 6" to 5" just as I require so I know it is possible.
Being so thin it will probably not make too much difference for the machine controller but the field crews using the SCS900 will lock on to my line work which happens to be the peak of the asymptote. This will probably cause them to read the finished grade elevation instead of the subgrade elevation.
I need to know if there is something specific I can do to remove these asymptotes completely. I've tried the standard Identify site regions command and a simple subgade adjustments. Both result in the same subgrade surface.