It has been a while now since I finished Jim's course, and I have had the opportunity to shoot many times casually with my friends, and one 3D tournament.
My initial concern about not being able to carry over the ability to make controlled shots when shooting with others proved to be groundless. I can make controlled shots under most conditions if I do everything else right. Stated another way, I never feel compelled to release the shot before I am ready. Jim's course is not a panacea for everything. If I don't concentrate, I will blow the shot. If I pluck, I will blow the shot. Both of these are examples of uncontrolled shots, but are different from feeling compelled to release the shot early, and there are specific things I can do on the next shot to correct these errors. Actually, before Jim's course, I never could have told you that I missed a particular shot because I wasn't concentrating, because all the shots were gone so soon I didn’t really know if I was concentrating or not.
One interesting, and somewhat ironic consequence of Jim's course happened during the 3D competition. I was shooting with a favorite competitor of mine, and I was cleaning his clock through the first half of the match. In the second half, my groups began to spread out and I began missing targets. By the end of the match, he had edged me out. The reason was that my strength began to fade in the second half. People noticed my bow arm shaking and mentioned it to me. I think the reason was that with my newfound ability to hold, I was using up my endurance sooner that I would have if I were rushing my shots. The match involved shooting 84 arrows at targets, plus whatever we shot in practice, or about 100 arrows total. This is more than I usually shoot with my friends in the morning. While it is hard to get stronger at 74, it is not impossible, and my new goal is to get strong enough to shoot 84 arrows without running out of gas. The only other alternative is to change to a lighter bow than the 40# bow I currently use for 3D and practice, but I love that bow and don't want to change.
The bottom line is that Jim's program will help you to build a strong foundation, so that the image of shooting relaxed and under control is burned into your mind, and this foundation will not crack under stress.