Unable to switch Bluetooth Host Controller?

I have a Mac Pro Silver tower running 10.8.4. It suffers from the Bluetooth Mouse stutter problem, so I purchased the only USB Bluetooth adapter I could find that said it was compatible with Mac: The Orico BTA-403.

I downloaded Bluetooth Explorer from the Apple Dev site, but I can't get it to actually activate the new USB adapter:

Even if I select the "Cambridge" Host controller, which I assume is the Orico adapter?, and click Activate, it doesn't actually activate. The Apple BRCM host still indicates that it is "[ACTIVE]"

I'm probably just doing something stupid. Any ideas what it is?