When using the Geometry > Vertical Curve Set > Add PI, Move PI, Insert PI, etc. commands there is no command window that opens so you can manually type in values for known station, elevation, grade, or distances. You can only dynamically place the point at an arbitrary location.
In order to manually type in values for precise placement, you can open the Geometry > Vertical Curve Set > Dynamic Settings command. Then when using the Vertical Curve Set tools to place and manipulate vertical PI points, you can set the values for placement in the Dynamic Settings box and they will carry through to the commands you are using to add or edit points.
This option is of particular importance when working in programs such as InRoads Site where you don't have the ability to edit elements through the Vertical Elements command to manually edit and adjust these points. If working in a program which contains the Vertical element tools you can also use the Vertical Element > Edit Element command to manually input values to adjust and move PVI points to precise locations.