This program has been 100% structured to give you real results. That being said, you must put in the work and be consistent with your practice. If you don't follow the steps in the program, you will not see results. In order to acquire new sounds, you must create muscle memory, which takes time.
Think of it as going to the gym. You wouldn't go to the gym once or twice and expect results, right? You need to deliberately and progressively train your muscles to get in shape. Your tongue, the main articulator in your mouth, works exactly the same way. In order to produce new sounds, you need to train it deliberately and progressively on a daily basis.