Essay structure question.

The method my teacher prefers is that we do the essay in three sections. For example, take the question "How effective at scrutinizing the executive is parliament?". He would tell us to first write a brief intro, then write all of the points suggesting that parliament is effective in the first section, then to write all of the arguments to say it isn't effective in the next section. Then write a conclusion.

But personally, after making a point i prefer to immediately pose the counter point, and come to brief conclusions on how valid each point is. My grades jumped from CCC in my first set of exams to ABB in the summer exams when i started writing this way. Which way is correct?