You will adjust, but I know what you mean.
I don't know why I first look at the lower mirror when I glance at either side? I had to train myself that the top half IS the mirror that duplicates the traditional mirrors that I was used to.
I suppose one of the reasons is that with traditional mirrors I kept them tucked in just enough to include the side of the truck in the reflection for visual reference. But with the tow mirrors providing the dedicated lower mirror for viewing the truck itself, it allowed me to push the top mirror "out" farther for catching more field of view of traffic. As a result my brain looks for the reference of the truck I'm in first, which draws my focus to the wrong mirror.
As stated, I had to train my brain to go to the top mirror for typical surrounding traffic data. I'm just about trained.