One of the many problems with the the AppleScript dictionaries for Mac Office was the inconsistancy with the “standard” suite. Office 2004 has a complete rewrite of the dictionaries and are MUCH more consistent with the "standard suite.
I missed the part where you wrote about using Office X.
I’m not seeing the same thing for Word and Excell. If both apps aren’t running, they open and quit. Most if not all apps behave this way unless they don’t respond to AppleScript at all.