The new Waves Central gave me a message that to install the plugin I wanted to install, ARR (along with the latest versions of several other plugs,) that all my older versions of Waves plugins would be uninstalled. I sat there several minutes contemplating if I wanted to do this or not.
Since I was doing a off-line install (another story altogether) I had to recreate the install package. Again!
After that installation went well, but when I started SPlat I had the same message about looking for the 9.6 version. However, I went about fixing it differently than what Eddie suggested.