Title says it all. I bombed the June LSAT (159) vs. my average preptest scores of 169. I attribute this decrease to a few factors: nerves, primarily, and the fact that my preptests were all generally older tests, so I had little exposure to the most recent exams. I've since purchased preptests 62 - 81, I use 62 - 71 as drills and 72 - 81 as full exams. Beyond that, I did not do 5 section tests and am doing that for all my full practice exams (2x a week).
My drilled sections are still timed, I'll divide tests 62 - 71 into sections, which I'll time myself through to completion. The only difference between these "drills" and a full timed test would be that a full test conforms exactly to the structure of the real LSAT, so fatigue becomes a factor.
Has anyone else had a similar decline in prep vs. actual scores? Further, do you feel it's reasonable to approach my practice scores by the September sitting? Initially my scores for 62-71 were lower, but have recently climbed up into the 169 range, and my full exam marks are still a bit lower, 163-167 range. (Fatigue is evidently a major factor for me!)
When are you planning on writing the exam? 146 - 170 is a huge leap, and while I wouldn't say it's impossible it will require a herculean effort.
To answer your question, I had a similar trajectory, in that I would plateau somewhat frequently, a big hurdle was breaking the 160 mark, and now breaking the 170 mark consistently. My last BR score was a 180, with a 169 actual score.
Certainly, understanding the fundamentals is, well, fundamental. So to break apart a test and not finish is certainly acceptable in early stages of your study, as long as you're getting 100% of the questions you do get a chance to get to correct. Even on my last test, a 169, I did not finish LG (the first time in a long time). You don't need to finish the exam to get a 170. Slow is smooth, smooth is fast, an expression I heard on the Thinking LSAT podcast which has been helpful to listen to during my commute.
But again, my biggest concern for you is the timeline you're working with. Can you achieve a 170? Absolutely. Could you do it by September? Unlikely, if that's your goal.