Actually I watched the vid yesterday and I thought you had changed positions somewhat. Go back over the points I made and keep them in mind.
Where is that last vid? I'll look....
Ok, yeah, there is like the slightest little difference but the problem is more in positioning. I think you need to get your shins closer to the bar. They can be right up against it or just a smidgeon away. Just remember the key points I gave you before. You should be fine.
It won't do you any good to abitrarily drop you butt and try to adhere to a certain back angle. This is just one of the two problems people have...1. stiff legging it and 2. "squatting" it with their butt way down low and back up right. The proper position will be somewhere in the middle and how to find that position is based on some simple guidelines.