Office Web Apps 2013 - Edit in Word Web App Disabled

There have been questions posted about this so far, but our situation varies a bit.

Similar to here http://social.msdn.microsoft.com/Forums/en-US/59ad19c8-492b-4077-b774-99b3f8c442d0/office-web-apps-edit-in-word-web-app-missing?forum=sharepointadmin

Edit in Word Web App option is disabled when in the viewer, but when going to edit in Browser from the document item context menu, edit pulls up without a hitch.

Our officewebapps.server.com/hosting/Discovery pulls up normally, Word bindings appear in it and the underlying file we are attempting to use is a docx file.

We have attempted to remove-SPWOPIBindngs and new-SPWOPIBindings, to re-bind things, but that didn't work either. Has anyone set up a farm recently and experienced this problem with SharePoint 2013 and Office Web Apps Server 2013, with SP1? Has any one fixed this problem without setting the Edit Word binding as default?

Thanks