My train of thought was that I would be able to devote all my time and energy to biochem alone if I took it over the summer sans distractions and other academic/extracurricular commitments. However, different students had different opinions on this take. The overwhelming majority agree with you though. I also have a mountain of credits to complete in 3 semesters so I want to make my fall and spring semesters as lax as possible by getting some of the difficult coursework out of the way over summer, even if it means studying day in and day out. I was also asked to be a biochem note taker and tutor for OLA in the fall which I'd love to do, but it would only make sense to accept the offer if I'd already completed it.