I think there's a bit of a false dichotomy at work here. The notion that being control means that you can stop at any point doesn't sound right. If you are doing a hard shiho nage, for example, Stopping mid-way could lead to serious injury for both you and uke. I think that the best measure of control is whether or not you are keeping good posture throughout the technique and able to maintain good balance and posture at the end. If you are out of control, you may stumble towards, or even topple onto uke.
Just my $.02 worth.