thickness of overlapping shell (mesh)

Hi all,

I'm trying to calculate the structural performance of the sandwich panel in Karamba. Before making them as mesh, I tested with simple geometries. 

I wanted to check how Karamba reacts on overlapping mesh.

As you can see the image as below, I tested 3 samples. 

I input the point load at the center to see the difference of deflection. 

The left one is a 1*3 panel with single thickness.

The middle one is two of 1*2 panel. There're overlapping parts of 1*1.

The right one is three of 1*1 panel. I doubled the thickness of center panel.

And, all the results are different. It seems that Karamba considers the overlapping parts anyway, but I don't know how it works.

For example, I want to overlap 2mm steel sheet in some parts. And then, is it okay to follow of logic of the right one? It means that I put 4mm thickness for the overlapping parts, and the panel should not be two.

Thanks for your replies.

Best regards,