In OPM U11 CE, By Default SWA (Solid Working Area) check is disabled in OOTB Environment and it simply ignores the difference in SWA. This document explains the procedure to enable Solid Working Area Differentiation Dialogue.
If above problem still persists, then please create a Service Request and contact the Bentley Product Advantage group. Please include a list of all relevant details to get in depth analysis for a solution or workaround.