I unfortunately didn't notice that it reverted the DLC discount when I unchecked the base game (since I had it already), so I was charged full price. Also, the GOTY hasn't kicked in yet.
So I messaged support, too. Hopefully it'll get sorted soon.
Rev1.0: Should I just install the Blood&WIne DLC on my "normal Edition", or is there some benefit in un-installing the normal Edition and installing the GOTY one?
Would the save games be compatible?
There's no benefit to uninstalling and reinstalling if you've already got the game installed right now (actually, it'd be
detrimental in that you'd need to download a much bigger payload and then wait through a full game installation process). The benefit to having GOTY will come if you need to reinstall in the future, at which point you'll only have to download and run a single installer.
Saves are compatible, yes. As long as you're running the same or a newer version as when the save file was created.