Since you are using a Content Control in the document, it would be better to link that to document metadata and then you can use the same content control in the header. This gives an instant update so you won't need to refresh fields to see the update occur.
See Greg Maxey's webpages for further information.
http://gregmaxey.com/word_tip_pages/repeating_data.html
If you don't use one of the built-in linked CCs then you should also choose to download Greg's CC Tools template which simplifies the act of linking CCs to metadata.
http://gregmaxey.com/word_tip_pages/...rol_tools.html