My analysis is that if you can't PR while listening to Rob Zombie, then obviously you've caught the ghey.
Several hours of Rambo and Chuck Norris Movies are the only cure.
But seriously, those vids looked pretty good to me. I didn't even see much if any funkiness when you hit parallel that I frequently see even in videos of squats.
I'm betting that extra volume before you hit that single is what did it.
On the subject of sitting back vs knee travel, here are some good questions to ask yourself regarding that.
Are my joints holding up to my current style? If your knees are giving your crap, then you might want to consider sitting back more.
Is my squat poundage going in the right direction? If not, it might be one factor you consider among others.
Whatever your doing, if it's working, I'd roll with it and just keep getting stronger to work through that sticking point.