I've modeled two meshes to understand their surface area variances but SolidWorks surface area calculations aren't making sense.

Modeled a 200mm x 200mm x 0.01mm square and it comes out to 88,000mm^2 rather than 40,000mm^2, 

Why does it take depth into account for surface area? I changed the depth and the surface area changed, but that's volume. 

Also when adding hole cuts to the modeled sample the surface