OP, you really favor the fast loop for BH. It can be done against underspin balls, but it needs more precision. You got the ball height and short stroke acceleration right to handle the quick ball into your body and BH zone. You cannot use this same stroke vs an underspin the same way and stay consistent. You could loosen up a little and use a little less power - you are gunna get a block back that your good BH fast loop will kill.

You would help yourself a lot to learn to make a real slow, but heavy topspin ball. You will get a lot of block and out or a ball to kill.

There are so many ways to hit your BH offensively… 

The successful BH you show in the vid is also a great kind of BH for those who loop medium spin deep to your BH. I suspect you would be very discouraging to such a player should they loop to your there.