If you do not want to keep a CS5.5 concurrent installation , this is the best way in my opinion.
The CS5.5 uninstallers do not remove everything of CS5.5 however. There will be e.g. left overs in the Help titles of the CS6 Help Manager. There is a cleaner tool: http://www.adobe.com/support/contact/cscleanertool.html
Thank you for this information and cleaner tool link.
I am assuming that, since I have the CS5.5 serial #, once CS5.5 is deactivated, uninstalled and cleaned up, I will be able to install the CS6 upgrade smoothly (if necessary, entering the CS5.5 serial # during the installation).
Hopefully, should work OK.