Delayed auditory feedback. Does it actually work?

Delayed auditory feedback. Does it actually work? I tried it for some time, but it wasn’t very helpful. The first time I heard about DAF it looked like a magical solution for stuttering with 92% of users showing improvement when using it so I don’t know what is wrong. Could it be that I am doing something wrong? Does anyone here use DAF in their daily conversations? Someone said to me that I shouldn’t be using fluency techniques when I’m using DAF is this true?