Look at the schools you want to get into. Do you need the extra 2 or 3 points? Can/want to put yourself through the work commitment that studying for another test entails? These questions you need to ask yourself. You are already at an incredibly high level and each point you go up will give you a diminishing return on investment. You are already better then 95% of the people who take this test. You might be better served by working on your essays and requesting letters of recommendation. However, if you have the time to commit and the will to go through another test. All the more power to you. Law Schools take your highest score so you won't hurt yourself if you get a lower score.