Section Modulus calculation and optimization

This is the minimum moment of inertia that i have got on my first step of the analysis.

I thought i can improve the strength by offsetting the inner panel by 0.6mm.

After offseting and calculating the modulus i have got a variation in the result and that was better than the first calculation.

This is the improved moment of inertia.

moment of inertia = 2.6249 

y = 438.08

section modulus = I/Y

                        = 2.6249/438.08

                        = 0.0059918