I assure you, when you ran the Berzerk installer, there is a little dialog box that popped open and said something about whether you want "ALL" updated. And listen, for years now people have been stung by this dialog box, because the word "ALL" could easily be mis-interpreted to mean you want all updates for just that particular plugin you are in the process of installing. What it actually means, and is not worded very well AT ALL, is do you want all your waves plugins updated. Then it systematically updates all your plugins regardless of whether you have the license for the newer versions or not. Totally lame, I agree, but still...all you have to do is make sure to not click OK when that dialog is presented to you while you run the plugin installer for the newer thing.
Listen I agree completely, Waves has a ridiculously over-complicated installation process, and yes its over complicated because they want us to only get updates, even simple version updates that bring no new features...by subscribing to an update plan. I also got stung by this exact thing a couple years ago and had to reinstall everything and I was annoyed as hell. But I can say now, it wasn't that bad once I figured out how to avoid clicking OK on that one question. If they have removed that dialog from the V11 process, that is not good, but I recently did install a V11 thing and I didn't lose any of my V10 or V9 things at all. And I'm confident it was because I did not click OK on that box like I did in the past. After that, if you did, then you will need to uninstall the V10 or V11 versions of the plugins you own V9 license for, and then use the legacy installation procedure to reinstall them.