algorithmic modeling for Rhino
You probably figured this out by now, or gave up. But I'm a noob having same issues. Found a thread which has a working script (morph 3dmean looks different, though). See link below.
The main difference is that instead of using geometry for SO, SBO, EO, and EBO, this one uses a surface. Not sure I understand why the other 3d morph panel tools use polysurface while this one does not. Seems rather limiting to me.