Nice progress, Yugo. I bet your consistent SMR work helped a lot in that.
I notice that you finish hard and exactly straight up in the latest video, whereas the finish is much sloppier early on. Do you think this is an inidicator that you are using mostly hips? I feel like vertical is sort of as far as hip drive goes, while if you're using your back extensors instead, you can go too far or not far enough more easily and your finish will be sloppy, slow and varied. I haven't seen that confirmed anywhere, though.
One thing I see in your latest video is it appears that you have managed to decouple your upper back and lower back's extension. I think your butt is at least as high at liftoff in the latest than 2nd to latest, but you have your upper back rounded over so that the angle of your lower back can still be steeper.
Rippetoe himself seems to do this a ton, and I think it's pretty standard for PLers:
http://www.allthingsgym.com/mark-rip...-lbs-deadlift/
But if you're not competing, I would think the same result would be achieved by using a trap bar or raising the standard bar a couple inches off the ground.