While editing a file, Microsoft office 2007 writes the content to a temporary file and renames the temporary file to the original file name while saving. When this happens the file's create time stamp will reflect the create time stamp of the temproary file which would be different from the original create time of the file. So after this happens, windows client will have to send a CIFS request to restore the create time stamp to the original value. However, this request will be sent only when the share permission is set to full control. In all other cases the create time will have the modified time.
1. Change the share permission to full control.or 2. Upgrade to Office 2010.
https://kb.netapp.com/support/index?page=content&id=3011249 Increase CIFS Max Multiplex