1- This is different, this is the “Plus” plugin, the one you paid for.
You DO need to download the latest version using your credentials on the site below and install that. Logon > Your Account > Your Licenses > View and Download
To manually install the latest version of Xtreme “Plus” Plugin, either use the “Easy theme and plugin upgrade” Plugin, or just delete the plus plugin and reinstall from scratch.
2- Regarding “Your site does seem to be using some kind of JavaScript / CSS “optimizer” that is changing the generated output of Weaver Xtreme. In general, this is a bad idea, and has been known to break Weaver Xtreme layout. “
Yes that would likely be a plugin you have installed to optimize javascript and CSS. If you did, you should remove that