Hi Mark - going the ‘other way’ maintains the curvature continuity in the surface, is all I am claiming, not that it makes the surface you want. Being curvature continuous is not in itself a measure of quality - you can get a ‘nicer’ flow and reflections if the transition part is more progressive, so to speak in its acceleration - these are both G2, but the nearer one is perhaps more what you are shooting for. Note the difference in graph on the red input curves
-Pascal