That's way to high... We use 800-1000, and yes the occasional instructor induced rope break at 600.
Of course there is always the instructor "my airplane" until about 500ft just outside the pattern entry, or the instructor distraction until the student cries uncle and wants to get into the pattern. Ahhh. Instructor, we are a little low out here, shouldn't we head in? Great observation, let's get this on the ground. Then the appropriate debrief on the ground,
BillT