The tips begin at a different place in each module. The advice moves along with the stages of the course.
A person will inevitably perform a large number of quantitative problems during MCAT preparation. Why do all this work? In the physical sciences section of your exam, you'll probably need to do math a dozen times at most. Most of the questions are conceptual. Why do all these quantitative problems? Firstly, you want to get those dozen problems correct. It's not huge, but they're important. Quantitative problems take a larger share of time per question, so you need to be fast with them, but most importantly, you perform the quantitative problems to gain tacit knowledge of how physical science represents the world. Quantitative problems build conceptual understanding.