This is something I've wished Autodesk would fix for years now.
Back with R14/Softdesk8, it was possible to do things like renumber points with an additive factor of +1 or +3, and everything went fine. Then it got broken when Autodesk turned Softdesk into Land Desktop, and it's still broken in Civil-3D.
Actually, I've long-wished that there were different renumber options, like the ability to key in a new start number (e.g., select some points, tell Autocad to renumber them starting at 5000). That way, the user doesn't have to calculate the correct + or - delta. I started to write a routine like this for the SincpacC3D, but trying to renumber points via the API in Civil-3D is problematic.
Sinc