Here are some screenshots to understand clearer...
This is with set size to "Banner" and position to: 1: "Bottom Center"; 2: "Bottom Right".
Samsung Galaxy Tab 4 (Android 4.4.2):
Samsung Galaxy S 5 (Android 5):
Objects are set to ViewPort Bottom-50. As you can see, it's ok on SGT4, but not on SGS5 (Banner is overlapping objects).