Hi Andy, curve to curve flow doesn't know anything about the surfaces. If you go from a straight line path mapping to another straight line path that's not going to produce any curvature in the result.

You could put in a plane underneath your text and use surface to surface flow or you could use curve to curve flow if you project a line onto your surface like this so that it has the curvature of the extrusion's shape instead of going in the straight line direction of the extruded top surface shape:





- Michael