We just installed a fresh version of Exchange 2013 on Server 2012. When our users try logging into OWA on a Windows OS (IE/Chrome) it uses the "Premium" version but on a Android 4.2 (Nexus 7) and Google Chromebook it reverts to "Light" once the users is logged in. But on either if we manually force the "/?layout=twide" flag for example it displays fine.
ADTU Enterprises