Old tests.... brutally difficult....
And not difficult in the way the AAMC makes some MCAT tests difficult.... the AAMC will hide basic concepts and in very confusing language and passages where the TPR ones are just obscurely awful questions going into detail way too far.
I have a feeling they are probably a lot like the cracking the CBT tests which are absolutely brutal and require a ton of recall, whereas the AAMC calls on your ability to derive the basic concepts from the passage and apply it to an answer, as you said, which I find much easier.
I do however really like the TPR tests, but you have to approach them correctly and utilize them for what they're worth (insanely hard tests). I am alternating TPR tests (cracking CBT) with AAMC tests and my breakdown has been TPR10 30 (11P/9V/10B), AAMC3 36 (12/12/12), TPR11 30 (10P/9V/11B), AAMC4 39 (14P/12V/13B.... made one horribly stupid mistake to keep me off of a 13 in V and cracking 40), TPR12 (11P/9V/10B). So I've been really consistent with the TPR tests, finding that each time there is some series of questions that stresses inane detail, but I do a thorough post-game every time which often fortifies my content review with a ridiculously detailed description of whatever phenomena is being tested (too much info can't hurt so long as you keep it all straight!). Along with being very consistent with the TPR tests I have found there to be no correlation between them and my AAMC scores, noting the AAMC tests to be much easier. With the AAMC tests being supposedly a much better MCAT score predictor I can't complain. The TPR CBTs are also great for timing because I've found they will often throw a huge random passage in the PS/BS sections for ONE QUESTION! You can't tell it's only going to be one because on the cracking the CBT tests they go question by question (not all questions pertaining to the passage in one shot). So if you can polish off the TPR tests in time, you should be fine for any of the AAMCs.
Think of it like weight training. In order to grow you need to put some undue stress on your body. These TPR tests are your dumbbells and barbells. Approach the test as if it is the real deal. If you get 10 questions in and go "Oh this is a load of crap!" you're not going to get anything out of the tests and you will probably not score nearly as high as you could have had you given it an honest attempt.
So in keeping that stuff in mind, I think the TPR tests are great for challenging yourself. They offer (imo) harder material than both Kaplan and the AAMC without the ridiculous Kaplan curve. Sure it can be a bit disheartening, but you have to keep in mind the difficulty of the test. If you can score a 30 on the TPR tests, you can damn sure score 30+ on the AAMC (and hopefully the MCAT???? I'll find out sept 12th
).
Edit: And Rayden, I have no idea how you can take a non-CBT format TPR test. At passage 4 on the verbal I always feel like dying on the spot because they have the most boring convoluted (and insanely verbose) passages haha. Knowing I have another few passages after 7 would probably legitimately do me in lol.