Revitotomy

As Autodesk Revit discussion group post - roof by footprint with differing plate heights 
<http://forums.autodesk.com/t5/Autodesk-Revit-Architecture/bd-p/133>

Is there a better way of acheiving this (screen snip attached). To get the roof segments off lower plate heights I have added in tempory walls corresponding the higher plate height, picked by footprint then extended the overhang on these segments to hit the lower plate height. Then erase the temporary walls. But this detaches the edit footprint-edit overhang function.
Is there a better way? If only a line element would host a roof to enable slope and overhang association