It may be that the quarter system school allows more elective courses, but each one is “smaller”.
That is really the basic difference between the quarter and semester systems – a quarter system divides the academic year into three 10-week quarters, versus two 15-week semesters. If the school is set up so that a student takes four 4-credit courses per term, then the quarter system will have twelve instead of eight courses in an academic year, but each of the courses will only cover 2/3 the amount of material.