What modifications are to be implemented, if the shear strain of a degenerated shell element is modified with (-2*w/Rxy)?

I had implemented Degenerated shell element by Ahmad et. al (1970). This element performs very poor in case of geometries like rectangular hyperbolic paraboloidal shells. When I modified the strain vector (only shear strain) with a additional -2*w/Rxy (Sahoo and Chakraborty, J. Strain Analysis (2004)), the solutions are not ok. Can you please suggest me if any other things I should be careful?