I agree with your technique; the concept of feet on the pedals and completely 'off the floor' puts the pivot point back at the knee with little possibility of the finesse needed for good control from the ankle movement that you use.
As a comparison, the best cyclic control comes from resting your forearm on your knee and using wrist and finger movements to control the cyclic. Try lifting your arm such that basic control is transferred back to the elbow. Difficult and clumsy, especially for a student.