It sounds like by "temperature" you're referring to the setting of your stove. If your stove is powerful enough that you don't need it at its maximum power to keep water at a rapid boil, then you can of course reduce the setting once you've returned it to a rapid boil (between your steps 3 and 4). On the other hand, if you have a smaller, older stove, you might need to keep it at high to keep the water boiling rapidly. So the answer is "maybe" - you do whatever you need to do with your stove to keep it doing what the directions say (boiling).
That said, this isn't necessarily the best way to cook pasta. You should test it, rather than counting on the time on the package to be accurate. And you don't actually have to cook it at a full boil, or boil the water before adding the pasta; see this great column by Harold McGee on cooking pasta in a way contrary to popular wisdom, and a Food Lab article based on it. You can in fact start with pasta in just enough cold water, bring it to a good simmer, and keep it there until it's done.