Keeping Uke Off Balance:

The most common problem that happens when a throw is slowed down to emphasize the details is that Tori loses the kuzushi he has applied to Uke.. Once he enters or positions himself for the execution of the throw he stops keeping Uke off balance usually due to his concentrating on the steps involved in entering and executing the throw. This defeats the Kuzushi that he set up previously to entering for the throw.

The key here is awareness and keeping the student focussed on the Kuzushi especially as he speeds up the technique and can perform it faster. He has to slowly going through the motions of the throw as to keep Uke off balance even when he's moving slowly