A small correction would help you understand better I guess. In the server when a qvw file is reloaded and stored, the account which is used is Service Account. So, ideally you should use your service account in the section access to have all field values (admin) that all users might need. That ensures the qvw file that would be referred by the UI client users would have all values, and the users would see their respective values only , So section access purpose is achieved.
To rephrase, the physical qvw file in the server would have all values , however, the users (using browser or other clients) would see only values pertaining to them.
