That is not what people are talking about....
For fast bowling along with the face buttons to determine length, one of the sticks are used to time the release of the ball. Depending on what length you choose and when you release the ball, final length will be determined. This way you can think of bowling a full length using face button but release the ball really late making the length almost short of length to counter an advancing batsman.
Now if you look at the controller pic, the sticks are not being used to time the release when it comes to spin bowling and hence people are asking what if we want to change the length in the last second and whether we will also have to time the release of the ball for spinners.