I was very skeptical this would work. At best I thought it would just barely be noticeable but I was quite shocked at how big of a difference it made. I will say it worked better on my CSFX than my Defiant and perhaps the 28" ATA helps amplify it. That said I don't like the way the video you linked recommends, at least if it's the video I think it is. Now he is doing it the correct way with keeping the left off module 1 notch(.5") under the draw stop setting, but his method adds an extra .5" to your draw length. The way I did it and the way I've seen others recommend is to keep the draw stops at your draw length but move the letoff one notch down. It creates the same effect but you are maintaining your draw length.There is a video on youtube titled "DFX Cam Let-off Improvement... EASY!" (I'd share a link but I don't have permission to yet.
great video on this, good luck!