There's a lot of variation in your performance on the LSAT, which can be down to all kinds of factors (even things like what you ate for breakfast) so I wouldn't read too much into slight variations, and would focus on the aggregate. The only way to get an accurate idea of where your problem areas are is to look at the cumulative data after answering lots of questions. Another issue could be with your stamina during long tests, which could be what's affecting your performance based on what order you're answering questions, which you can only really improve with practice. My main advice would be to focus on the question types you consistently struggle with and not focus too much on drill to drill variations, and make sure you're practicing consistently and mindfully. The real way to improve is by identifying areas you struggle with and finding those gaps in your understanding so you can correct them. Wishing you luck on your LSAT journey!

I would suggest using 7Sage's study plan and sticking to it as much as possible, but if you want to add a section of LR every other day or so while you complete your lessons I don't think there's a real downside to it. The only risk is using up all your available material, so if you're not making progress after a week or so you may want to be careful you're not wasting your pool of questions. Otherwise, if you think it would help you retain what you've been learning, or you're just feeling motivated, I would say go for it!

I think you're fine to use them to track your progress, but you should use your PT average (once you've taken enough for it to be representative) to gauge if you're ready for the real thing. There's a big opportunity for disconnect if you have issues with the length of the test or stamina. Say you can always get -3 on your first section, but as the test goes on you get -4, -5, -6. The PT equivalent on sections is only going to capture that -3 first section score, and not that you do worse over time. Hopefully that makes sense!

I would always be hesitant to use one of your limited attempts if you haven't diagnosed and addressed what went wrong. 162 is pretty far from your average. It could just be an outlier and you got unlucky. Maybe you will do closer to your average on another attempt, but there could be an issue somewhere that is causing you to score lower on test day. One thing that helped me is trying to take practice tests in unfamiliar / slightly noisy environments to simulate test day, like coffee shops and the library. When I started that my score plummeted, but I was able to improve it with practice. I think this helped me on test day considerably. If the issue could be the testing environment, it could be good to try this out for at least a couple of weeks and see how it is.

Here is one that I use, it is not comprehensive and doesn't include the valid/invalid arguments, but I hope it helps some!

The good news is that the LSAT is learnable and you can master it. I can't speak to your admission questions / frustrations but it is certainly possible to go from a 157 to 170s. I would stick to your study plan and make sure you're drilling consistently, and working toward full sections and PTs over time. It sounds like you can get questions right when they're lesson examples, but struggle when actually taking the test? This could mean your issues are timing or stamina with sections, which can be improved with practice. I also began my LSAT journey while working full time, and I promise it is possible. It could also be that you have some fundamental issues with your understanding somewhere, which I would certainly suggest sticking with a study plan and following the 7Sage curriculum, once those pieces fit together the LSAT becomes much easier. You can also track what kinds of questions you're getting wrong to potentially diagnose places where your understanding isn't quite there yet. The LSAT is a marathon, not a sprint, but with consistent practice you can get where you want to be.