This thread has some explanations on it, starting here. Basically, all pumps do their extended the same way. They just use different names. They are all the exact same. And yes, if you want to think of an extended as an increase in basal, it is the all the same to your body. It is not the same as doing two shots.
You could do two boluses instead if you wanted to. All kinds of ways to do it. The problem with doing the second bolus is just if you forget.
Anyway, check out this thread and then let me know if you have questions. Happy to answer for you.