One of the nice changes that you get when you install Service Pack 1 for Civil 3D 2005 is that several Subassemblies get updated and now have a new capability.
Specifically, LaneBrokenBack, LaneInsideSuper, LaneOutsideSuper, LaneTowardCrown: Added a runtime logical assignment that allows the user to tie the elevation of the outside edge-of-lane to a profile.
Occasionally, I found that I wanted to use the old versions but without the ability to attach them to a profile they had slightly limited use.
The issues resolved were good to have. But, this was a nice little surprise.
By the way, I had no problem installing the Service Pack.