I only bother with that if theres any glitches or problems.. If there is problems, uninstalling and running Driver Cleaner Pro has solved pretty much any problems I've had with AMD cards/drivers..
The crossfire profiles, or "Application Profiles" is what AMD call them I always uninstall the old ones before installing new ones..
Haven't had any problems lately with installing on top, and I can't be bothered when it works perfectly this easier way
Amd deisgn those drivers to be installed over each other, I never had a problem untill i once uninstalled some and installed a newer version that's when i had a problem, But i bought a SSD just after.. back to just install over..