Report all EPMdocuments last modified and checked in between 2 dates

Version: Windchill 12.1

Use Case: I am trying to create a report that will tell me which EPMdocuments have been created or changed in the commonspace between a given date and today. I am only interested in the latest version and only standalone models and generics (no instances).

Description:

I have created a report that indicates all EPMdocuments last modified in the given date range.

BUT the main problem is that it isn't limited to just the objects in the commonspace. It includes workspace object. It lists objects that a user has created and uploaded in a workspace (but not checked in yet) and existing objects that have been modified and uploaded in a workspace (but not checked in yet). 

There are fields in the EPMdocument that would seem to allow some filtering of this, but they don't seem to be accurate, at least at the level of the last modification.

There must be some way to report only on the commonspace changes, but I'm not seeing how to do it. I thought this would be pretty straighforward to do, but no.