As of now I have not pitched my tent in either camp. There are factors in both systems which could cause changes in the pressure. Keep in mind what is normally measured is Max chamber pressure, while in reality we have a pressure curve extending the length of the barrels. Max pressure will normally occur just as the charge starts to move. There is no doubt the forcing cone can have an influence on the pressure curve, but it may not actually raise the max pressure as the charge is moving & pressure is falling prior to hitting the cone.
