Yup you don't need that extra spline onthe top face (red).
Make the end (green) out of one single spline loop, extrude it twice like the arrows show, peak everything, and then neither the ends nor the middle will show a patch.
If you made this by first creating the L-shaped cross section, then extruded that down, that will almost certainly create internal patches since the ends and middle would be made from more than one spline.