Ssouki,
Great question! PowerScore recommends that you start by reading the stimulus closely...Primary Objective #4, which you note, is simply a reminder that when we read *any part* of the question (stimulus, question stem, or answer choices) we must read carefully and know what the author has said. It is not, necessarily, a requirement to go back and re-read the stimulus.
That being said, what you do is going to depend to some degree on the question. On an "easy" question, it may be sufficient to read the stimulus, read the question stem, prephrase an answer, go through the answer choices and confidently select one answer. But of course, some questions on the LSAT are not so easy
so for tougher ones you may have to read the stimulus a couple of times to fully understand what the author says. That's the key: without understanding the stimulus, there's no hope of correctly selecting the right answer choice...so if you need to go back and re-read, do it! But it's not necessarily a requirement for every question.
One last thing: some test-prep companies will recommend reading the answer choices before the stimulus so you can have an idea of what to look for. We don't agree - what we find is that students who do that end up reading the answer choices to start ,reading the stimulus and question stem, and then having to re-read the answer choices because it simply isn't possible to remember them that long. So start with the stimulus, work your way down, and use the Primary Objectives to help!
Hope this helps!
Alex