You're kinda missing the point of the curvature comb, aina hey? The length represents the amount of curvature. If you want constant curvature, try an arc.
Are you referring to the "dip" at the interim point of the spline? If so, click on the spline and then in the property manager reset that handle and/or relax spline. When adjusting interim points on splines, hold down the <ALT> key when dragging the magnitude to keep the value equal on both sides of the point (this will help with smoother curvature), if possible per your design intent. Otherwise, try out the Style Spline which does not work like the default Spline in that it is a single Bezier curve with orders of degree that you can assign.