Pft, "toughest high school" just wait till university
I went to your rival school SWC, was in IB, and some of the dumbest of my peers would be above average in IB.
I think you confuse homework with understanding. If you have no idea what your doing, then yes you should be studying. You study until you understand it, there's no point in putting a time limit on it.
What I object to is the "here is how you do derivatives, now do questions 1 to 250" - you got to be joking. After the 5th time, I think I know what I'm doing. Understanding enables innovation, but repeition kills creativity. That's the buttom line for homework.
In university (engineering, at least... 4th year) you do a total of 15 total questions (worth assignments) before you write your midterm, and 25 total questions before you write your final exam. If your lucky, you get examples. I don't get any examples in one of my classes (plasma physics) just theory, so your left to decifer what this linear algabra within partial differential equations is supposed to physically mean (its not "just math" but you have to know what those damn equations mean, and where they come from). Not to mention it takes an hour to do one question too.
A couple coarses in university I don't have to study for (logic... economics... volts for dolts... teaching engineers about management) ... but almost everything else, I do.
Study until you understand it. Give it a whirl or two. But once you know it, no point beating down the same path, or else your just a monkey jumping through a hoop.