Tap detection on Android

Hi

I'm trying to get a "tap anywhere to drop the cargo" behavior while at the same time allowing for camera movement using swipes.

What I have works perfectly on some devices, on and off on some others, and not at all on a few devices, which is very annoying. Am I not considering something here? Here's what I've got so far:

 void Update()
     {
         if (1 == Input.touchCount)
         {
             switch (Input.GetTouch(0).phase)
             {
                 case TouchPhase.Began:
                 {
                     buttons[0].wasDownLastFrame = true;
                     buttons[0].origin = Input.GetTouch(0).position;
                     clickWindow[0] = Time.realtimeSinceStartup + clickTimeThreshold;
                     dragWindow[0] = Time.realtimeSinceStartup + dragTimeThreshold;
                     mayClick = true;
                     break;
                 }
                 case TouchPhase.Ended:
                 {
                     if (mayClick && !hasDraggedTouch && !InputUtilities.IsPointerOverUIObject() /* && Time.realtimeSinceStartup >= clickWindow[0]*/)
                     {
                         MessageDispatcher.Instance.DispatchEvent(new MouseClickEvent(0));
                     }
                     MessageDispatcher.Instance.DispatchEvent(new TouchDoneEvent());
                     hasDraggedTouch = false;
                     mayClick = true;
                     break;
                 }
                 case TouchPhase.Moved:
                 {
                     if (Mathf.Abs (Input.GetTouch(0).deltaPosition.x) > dragPixelThreshold && Time.realtimeSinceStartup >= dragWindow[0])
                     {
                         TouchDelta = Input.GetTouch(0).deltaPosition;
                         MessageDispatcher.Instance.DispatchEvent(new TouchSwipingEvent());
                         hasDraggedTouch = true;
                     }
                     mayClick = false;
                     break;
                 }
                 default:
                 {
                     break;
                 }
             }
             lastTouchCount = 1;
         }
         else if (2 == Input.touchCount)
         {
             mayClick = false;
             if (TouchPhase.Moved == Input.GetTouch(0).phase || TouchPhase.Moved == Input.GetTouch(1).phase)
             {
                 MessageDispatcher.Instance.DispatchEvent(new TouchPinchingEvent());
             }
             else if (TouchPhase.Ended == Input.GetTouch(0).phase ^ TouchPhase.Ended == Input.GetTouch(1).phase)
             {
                 MessageDispatcher.Instance.DispatchEvent(new TouchDoneEvent());
             }
             lastTouchCount = 2;
         }        
         else if (0 == Input.touchCount && lastTouchCount != 0)
         {
             mayClick = false;
             MessageDispatcher.Instance.DispatchEvent(new TouchDoneEvent());
             lastTouchCount = 0;
         }
     }