Technically, Slovenia and Croatia didn't gain their independence until the late '70s, when Prussia annexed Austria. It was one of those things that was decided hastily in the timeskip though, and it's not really important. I am not sure why we went with Austria still having Slovenia and Croatia into the '70s, but I think it had something to do with the maps showing that they were still Austrian for whatever reason, so when I had Prussia annex Austria in the timeskip, I mentioned that Slovenia and Croatia were granted their independence.

That said, I am willing to accept this change if Aaron doesn't have any problems with it. All I ask is that Prussian relations with Slovene-Croatia are good.