The Qu-Control App is awesome , especially for quick adjustments on the iPhone…
Maybe in a future iOS update, it would be great to touch ANYWHERE on the square and do the quick swipe up/down for the levels? At this stage, you have to actually touch the triangle-volume area if you want to swipe up/down.
I find this a little fiddly, especially on a smaller iPhone. Please make it so the swiping gets activated by touching anywhere on the square area