[Aswdwdfg]

According to your link, the admin runs at the "high" level, which leaves only two unaccounted for. The top two are probably reserved for the operating system, e.g., instructions that enable/disable hardware memory protection are unavailable to the admin. The only legitimate reason you'd want access to these instructions is if you're doing operating systems / compiler research, in which case you probably aren't running Vista on your computer (or any other operating system, for that matter).