Sorry to hear your having problems. Here's a thought. The guy that posted in the Hustler forum that said he was from one of the distributors and was working with hustler engineers trying to solve the cut problems said that this deck was creating too much airflow and was causing it to blow down some of the grass and not cut it. You could try slowing your engine speed a little and see what that does. I would think that may do something since the the blades wouldn't be turning as fast and therefore creating less airflow. You could try it.
Do you have flex forks on yours? I was mowing again today and i'm just not to happy with them. The machine bounces up and down and leaves a choppy cut and scalps worse. I'm running 10 psi all around. it may help if i lowered it to 8-9 but i don't have a guage that reads that low.