Keep using it, keep practicing. Remember, it is a supplement to help you get more points out of the verbal section. You still have to read the passage.
You are going to use it on the real MCAT when your brain is exhausted and you can't even think straight on the verbal section because the passages are so hard, and you are desperately looking for any extra information that will help you answer those questions.
On some questions, it will be less useful than others. For example, q.1 on passage I of exam 1 is one example of a not-very-helpful question stem. But, there is still a clue there: ..."in the sense of..." immediately tells you that asphalt is probably wrong, and stick is probably wrong. Then you can go back and check the line and the answer is obvious.
The whole idea of this technique is that there's a lot of information in the question stems, and that if you don't take advantage of that, you are throwing away potentially useful information.
good luck!