Advice for more recent PTs vs old ones? (Aiming for 175 LSAT)

I'm taking the LSAT for the third time in November, and I'm honestly feeling a bit discouraged. Whenever I take the older PTs, I do well: on PT 134 and 132, for instance, I scored 178. On the more recent PTs (150s), though, I don't do nearly as well. I just finished PT 155 and I'd felt quite confident about my performance on the LR sections, but I scored a 170. I don't want to give up on getting a high LSAT score, as I think I have the potential in me, but I'm not sure how to proceed.