If I'm not mistaken, the MCAT scores are curved to a mean of 500 and some previously determined standard deviation, so taking the MCAT during the school year when you're also taking classes shouldn't really put you at a disadvantage because you're only competing against other test-takers who are also in school while studying/taking the test. If you take it at the end of summer, you're competing against test-takers who spent all summer studying and preparing for the test. Why, then, is it "common wisdom" to avoid taking the MCAT during the year if you have to study for it and take classes concurrently?