Not to sound unsympathetic, but your scores aren't really that far outside of the normal margin of error that LSAC admits. (+/- 3pts). The first test was strong, but it is possible that was the one that kind of hit your strengths. Based on those scores, it would seem your skill level is around 163-164.
This pattern is also pretty common if you started studying from books/classes shortly after your first test. Many people find that they will experience a little drop in the first little while after starting, since they are trying to apply skills that they haven't yet mastered. I would look at the 163 as encouraging though, and it may indicate that those skills are starting to make a difference, and your score is on the upswing.