Hmmm
Something is not right here? Firstly if you do not get on with an instructor, have a clash of personality or do not trust his methods or advice change instructors!
My guess and its only a guess is this instructor is one of the glide approach instructors plus!
He will have you coming down a steep glidepath throttle closed, full flap at 70 knowing because of your steep and draggy approach as soon as you flare the speed will quickly drop off!
Do you notice the throttle in the descent? Is it almost fully closed on teh way down and is your descent steep with a lot of drag hanging out.
More detail please
Pace