I like what Charles Staley recomends dont focus on the breathing just make sure you do it. In other words let it take care of its self. Breath in a way that feels natural and comfortable to you.
Also in big compound moves, squats, dl's bench, etc, by holding your breath you are increasing abdominal pressure and making a solid core base.
I personally do the same as you and hold it through the motion until I am clear of the sticking/tough part of the range of motion. Near the end. Breath and go again.
Just dont go multiple reps or extended periods holding that much pressure.
Thats my take anyhew.