Hi @Anonymous,
Thanks for contacting Autodesk Community Forum.
I have tried to create a macro for the above requirement but I am not able to input a point inside the limit wizard in order to cut curve at that point using macro in PowerShape. I have raised a change request for this behavior and I will let you know once I would get feedback from the development in the respective change request.
Thank you for your time and co-operation,
Jitendra Chaudhari.