I would like to know though - if you were doing an exercise you didn't realise was incorrect, would you appreciate a PT showing you the correct way?
In short no. I've had too many PT's pull me up for squatting below parallel because it will DESTROY my knees.
Just because they think it is correct does not always make it so.
Edit: Hi & welcome to the forum I'm sure your a competent pt but there are some shockers out there.