Do you have event points at these locations? Or some other reason that you could generate a report on these points using Station Elevation for the P.G. point?
If you can create such a report, you could bring it into Excel, setting the Station format to be xxxx.xx (no plus sign) and in Excel, use that data to generate a script file using SE=(station_value),(P.G._Elevation+vertical_offset_value) and then use the script file as input while in a Place Vertical PI command.
Or use Excel to create an ICS input file to create a vertical alignment from these values.
Or use Excel to create a script using SO=(station_value),offset_value,(P.G._Elevation+vertical_offset_value) and use that script as input to the PLACE LSTRING SPACE command to draw a 3D, non-planar linestring.