I've given you two good references on the STYLEREF field. Suzanne Barnhill says that the field is surprisingly well documented and I have to agree. Here is the official MS page.
When used in a header or footer, this field implements in real time. If you change the text in the reference style, the field updates as you make the change. When used within the body of a document, you still need to update the field in some way.



As for the REF field, make sure you do not have a MERGEFORMAT switch in your field. If anything, you would want a CHARFORMAT switch.