With the protection methods available, most users can be prevented from changing anything that shouldn't be changed. Another approach, which few users could get around, would be to use secure PDFs. That'll require a completely new approach, but it does have the benefit of allowing you to lock them down so tight they can't be printed or their contents copied (if that's what you want to do).
Doesn't your boss realise that, once the document's open, the users can save it locally anyway, and then work on it?

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]