You will probably also find that it will not work unless you turn off all the spellcheck and grammar features as seen here. Please note that when replacing text in the document, word's spellcheck feature distorts plain text that it sees as misspelled words by wrapping parts of that word in question (my_dynamic_file_title) in spellcheck and grammar tags. docx files I learned that it was easier to edit files as seen here. So early in my venture to create dynamic. I could not achieve adding the protection on the fly with PHP at this time.
Quickly: This is the easiest and first way I have found to get 'close' to achieving tamper proof.