Rudder Shape

Rudder shape
Last year I replaced the rudder and rudder box in my 86 comp. When it came in the mail it was the new style shape rudder the comes on all of the new boats . I called the dealer and asked if the new shape will make any different in how my boat performs . His answer was that it will handle the same ,this is the up dated style he is in stalling on all of the rudder replacement jobs in his shop. All I will need to do is file the back edge of the blade to adjust the amount of pull I like or (rudder torque) .
At first I thought that the rudder was going to be OK but now after a summer of tweaking I have come to the conclusion the new shape dose not work on a comp. Mr. Fowler picked the shape of the rudder for a reason.
The boat dose what I think is called over steer . When the boat is put in to a left turn the pull changes from right to left . This gives the feel of out control as the slack is taken up in the steering cable. When the boat is in a right turn the pull increases. Also when the power is pulled back quickly the pull changes from right to left. When I change props the symptoms change slightly I have never noticed a change in the steering when changing props before.