I think there's a lot of confusion and misunderstanding about this security flaw.
First of all, you do not need to apply the patch; the flaw in BIND will not affect you unless you are running your Mac as a name server, for example if you are the owner of an ISP and you use Macs as DNS servers. If you are just a consumer using your Mac, then patching your Mac makes no difference. The patch only affects if you happen to be running the name server software called BIND on your computer and using your computer as a name server.
The thing that tells if you are affected or not does not tell you if your computer is vulnerable. Your particular computer is never vulnerable if it is not running as a name server. Instead, that test tells you if your ISP has fixed the problem on their name servers. So it is possible that you may not apply the patch and you'll get an OK response from the test, or you may apply the patch and get a not OK response from the test, because the test does not test your computer at all. It tests the computers in your ISP's data center.