Design of Flat Slabs using SAFE

Why not switching to thick-elements? SAFE supports that type of slabs as far as I remember...

Structural Analysis of 2D Structures software
Static, Dynamic,Linear and Non-Linear Analysis
of frames, trusses, beams etc.

But all the classical literature's on Flat Slabs use Flexural elements (i.e with only transverse bending deformations, no shear deformations(in-plane nor out of plane)) for analysis.

I would also like to add that I have observed no significant changes in the analysis results when analysed using Shell elements.

When exactly will you go for using a shell element for analysis ?