If i may make a guess CC is using a messed up either mesh loader or storage script. The Headshot 2 mesh is low poly as well, see my last post under Official Issues.
RL products do NOT alternate poly count on import. You can verify that by looking at the poly count statistics or enable wire-frame mode.
Smooth Mesh is an internal, virtual routine which is subdividing/tessellating the mesh.
At some point RL implemented FBX/OBJ Export of the virtually subdivided mesh (you have to explicitly check mesh subdivision box on export panel) to bake it physically (tessellation smooth is not exportable).
Depending on UV and topology, mesh subdivision in CC in certain cases may invalidate texture layout over the UV and even distort the overall object shape. In which case subdivision has to be done outside of CC (like in Blender) with some additional tools and advanced subdivision options.
ANY mesh which does not have Smooth Vertex Normals applied, would appear bulky/flat with visible sharp edges (this happens a lot on import and depends on FBX/OBJ source). This does not relate to low poly count or subdivision in any way.
To smooth flat faces after the mesh import in CC you have to go to Mesh >Edit Normals and use AutoSmooth with appropriate angle. This routine does not change poly count as Subdivision Smooth does. But rather “fake” a smooth transition between 2 neighboring faces. This is a fundamental principle in 3D shading.