And I have done many flight reviews with students that reduce power
abeam the numbers and then desend to about 300 feet while extending
there downwind to landing traffic. Then the fly the base and long
final at 300 feet.

A much better technique is to fly the extending downwind, base and
maybe even part of final at a 1000' AGL. Once within gliding range,
then reduce power. At least at 1000' feet you should have 20-30 seconds
to consider you options of where you are going to land should the
engine fail. At 300' your going to hit what ever is directly in front
of you.

Brian