Need help on sat writing verb tense

<p>Okay so I was studying the McGraw sat writing book and it said when a sentence contains two past tense verbs, check whether one event was completed before the other. If so, the earlier event should be in the past perfect tense. For example,"we had eaten the pie before Ellen realized it was missing."
So for "when I got home, I wrote an essay." why is it not "when I had gotten home, I wrote an essay." don't you have to get home before you write an essay? Someone please help. Im lost!</p>