There are some clear disadvantages to taking the February LSAT. Nikki Siclunov wrote a good article about the reasons to take or avoid this exam date. You can read that article here: https://blog.powerscore.com/lsat/why-do ... even-exist
The downsides that Nikki points out can be unfair, if you absolutely need to take the February exam and only the February exam. Of course, no LSAT is exactly the same as any other LSAT. Certain questions, passages, or games can play to your strengths or weaknesses. For that reason, taking just one test is risky. As Dave Killoran has pointed out, "Welcome to the LSAT Casino!
The point that you brought up concerning challenges to a specific question is different from what the above articles address. If there happens to be a question that you answered 'incorrectly' due to ambiguous wording or a biased topic, then it would certainly be unfair to not let you challenge the result. This is extremely unlikely to ever happen to you.
First of all, the LSAC applies the same standards of evaluating the validity of answers to the February exam date as it does to every other test date. The questions you answered on the February exam were scrutinized by a number of intelligent and meticulous people. After being verified by these folks, the questions are tested on thousands of test-takers in their experimental sections. If there is any statistically aberrant result, the LSAC will remove that question before you see it on a real section or alter it to eliminate any ambiguity.
Sometimes a poorly constructed question slips through to a real section. This happens very infrequently. A quick search tells me that it occurs on fewer than 10% of exams. (I am not aware of any tests in which multiple questions were removed, but please correct me if I am wrong on this point) The majority of these questions were removed from scoring before the exams were graded and sent back to the test takers, meaning that the LSAC caught many of these mistakes before anyone was given a chance to challenge the results.
Furthermore, You are presenting a situation in which you were unfairly marked down for your answer. However when a question is removed from scoring there are test-takers who benefit from that removal, and there are test takers who do not. If you answered the poorly constructed question 'correctly' you might be frustrated that some other test taker challenged and had a question that you got correct removed from scoring.
Finally, there is no guarantee that getting that one fewer question wrong would help you out. Suppose that you answered 74 out of 101 questions correctly on the September 2016 exam. If you were to have found an ambiguity in a question that was marked incorrect and you won your challenge, the scoring scale would have shifted down by one question on that exam date. This means that your 74 correct answers out of 100 questions would have gotten you a score of ... 160
. Exactly the same score as before.
Let's say that your score were to increase by one point after winning a challenge. If you feel that an increase of just one point would increase your odds of getting into your dream school, then relax, because you can get that score increase on the June exam. You may have been set on applying to schools this cycle, but a little bit of extra work between now and June means that you will have much better chances of getting the score you need. So focus on what you can do right now to help yourself out, and get studying!