Even if you land at a higher airspeed, as the aircraft slows down you will get to a point where you have maximum rudder deflection and you will begin to drift off downwind before it is ready to settle down on the runway. Once you go beyond the maximum demonstrated crosswind you are a test pilot and I echo Keygrip's comments - your school are putting you into a difficult and dangerous position by letting you go off on your own when you still have some questions unanswered.
Remember if anything happens and you get injured, you are the pilot in command and it will be your fault.