The scores for the end of the chapter aren't indicative of how you will fair on the MCAT. They are a gauge of how well you understand the content that was presented in that chapter and outside knowledge , which sometimes with TBR , maybe preceding/proceeding chapters or just things your should probably already know. The latter is rare for TBR they seem very comprehensive so far in my opinion. What you should be thinking is why did I only get 60%? How can I improve? What content did I not retain/understand. How well you ask yourself these questions and how far you are willing to to go to answer them will determine your MCAT score.
That is why a majority of people on here claim that doing problems is so crucial vs. content review. Doing problems reveals your weaknesses in applying the knowledge. Doing content review lulls you into a sense of false security just because you read something once doesn't equate to mastery.Once you fill in the gaps or fix errors in calculations for example don't say to yourself "Ok.... I am done with that," Make a separate notebook by sections with problems and concepts you are shaky on. Be verbose and put your answers in terms you can understand or recall quickly. The most important part is to actually open this notebook and read from it everyday. Think about this if you are willing to spend numerous hours reading for content review then it only makes sense that you would allocate as much or more time to the things you don't understand after doing the end of chapter questions.
I use anki to keep everything fresh, I find that taking notes in a question format, rather than just righting massive amounts of text is way more beneficial. I kind of stole the idea from SN2, instead of the hat trick when I find something I don't think I am strong with, I will figure out exactly how to apply it and then write an MCAT style question that will appear in my set of flash cards. Every question I miss gets put on a flashcard as well with a detailed answer and why my thinking was incorrect or whatever math error etc.
For what it's worth I was pretty demoralized with my scores at the end of the chapters, but then I started thinking about it as a blessing more than a burden. The blessing is that my weaknesses are right in front of me ,there is no ambiguity just straight forward right or wrong ......and now I know what I have to work on. I would much rather know what I suck at now as opposed to the day of my MCAT.
As far as your test date you should think long and hard about where you are at and where you want to be. If you don't have the time to do what is necessary to improve you should postpone. If you rush yourself and end up with a low score you will be reapplying and retaking anyways, better to do it once the right way in my humble opinion. Also, I would be very careful taking advice from anyone on the boards as to what you are capable of ....only you know that. How can anyone truly tell you that X amount of time is enough to study when they have never even met you. You might be the person with sick recall who can look at something once see all the angles and apply it, or you might be the average Joe who runs into some bumps along the road. I would take this opportunity to be very honest with yourself as you are the only one who knows what is best for you in your current situation. Above all good luck!
