Is it possible to have prismatic coefficent greater than 1.0? Please see attached file. It is a regular dinghy hull.
Your midship location is placed at 8,544 ft.
the biggest section area seems to be at 3-4 ft (section area curve)
thats why it is bigger.
I guess your midship location has to be set up to the highest point of the area curve (3-4ft). Than the CP should be correct.