So if you don't want it blowing on your arm/face, yet you already have another window near the window that is closed. What is the point of even leaving the mode where it would blow from those vents?
Cause with the open/close slider, you can adjust how much air actually come out, and if one of us prefers air from one, but not both blowing at us, then we can turn one off and leave the other on. Every car I've had or been in either had the open/close slider, or would actually close all the way if you adjusted the vents properly.