Content Administrators should be able to edit any page. If you add a user to the Content Administrators role (or any role) they need to sign out and sign in again in order to get the new role cookie.
If you feel it is not working like that please try to reproduce the problem on demo.mojoportal.com and then tell me the user and the page that he should be able to edit but cannot so I can see it.
The only pages that Content Administrator should not be able to edit are pages with only the Administrators role enabled for editing, if no other roles are allowed then it limits the page editing to only Administrators. If this is not intended then don't specify the Administrators role in edit permissions at all since it is not needed, Administrators can edit anything without specifying Administrator role permissions.