I don't have much use for Quick Profiles, beyond being Quick. I haven't exploded or exported them. If I need that data, I'll create an alignment.
I don't think I will create an alignment out of a 3d object to begin with - it kinda begs the question and as you noted seems to be the root of the problem. A 3d object has a long 3d Stationing as it goes up and down.
A defect - looks like it - the profile stationing should match the alignment stationing. It appears the profile stationing inversing includes the Z in determining the length, where the alignment stationing does not.
I would suggest not using a 3d object to define something intended to be flat.
Matthew Anderson, PE CFM
Product Manager
Autodesk (Innovyze)