One group of senior colleagues found an error in opposite faces of extruded features both ways either by direct solid extrude, or forming solid from closed extruded surfaces. That is opposite face have different area when we used a part of spline to form a closed loop, or curve defined by equation. That error not only questions about the result of their study moreover questions about SolidWorks capabilities. Is there a way to resolve this problem? Now they are thinking to move on Non dessault software like Creo parametric or Unigraphics.