Some folks like you start with the hips a bit low and hips rise to your strongest starting position then the bar leaves the floor.
I've watched my coach and others try to correct this by having you set up higher. For example, set up with hips low, then rise to ideal hip position then start to pull. But you seem to pull form a low hip position, but as Chris states the bar doesn't break the floor until your hips rise to the more natural starting position before breaking the floor.
All that said I don't know what the drawback is with your technique even though some say it's not ideal.