another point -
Okay, you have executed a well banked final turn no lower than 300 feet, and have nailed the approach speed for the conditions of the day. However, as your reference point begins to slide gently up the canopy, you realise "o dear, I think I am undershooting!"
PUT THE BRAKES AWAY COMPLETELY! NOW!!!. and when re-established on the correct approach path, you may open the airbrakes to the appropriate setting, which is usually 2/3, in a K-13, to the height of an average elephant. Now looking well ahead, begin the progressive roundout, or flare, resulting in gently settling, to the perfect landing. Fully stalled, of course, to avoid any chance of the dreaded balloon!
Ask your instructor to demonstrate first, the perfect landing. Then fly again, and this time, you do the perfect landing.
A good landing is a stall near the ground.
However, OVERSTEER, if you are flying a discus, you hardly need to worry about opening the airbrakes whenever you jolly well like, the discus is an advanced glider with no vices, and as you of course are well experienced, and flying at correct airspeed even in a turn onto final approach, highly unlikely to have any problems. These warnings are aimed at beginners.