OnMouseDown is checked when build for Android

I have an question.

For example I have two function, One that is getting the OnMouseDown event when Im in the editor and other one when Im getting touch inputs when Im getting the app to android.

 #if UNITY_EDITOR
     void OnMouseDown()
     {
         //if the state is in Motion then we can't click on other matches 
         if (GameObject.Find ("Board").GetComponent<Board> ().DetermineBoardState())
                         return ;
 
         //This will ensure us that if the objects are swapping than we can't swap other objects.
         if(!GameObject.Find ("Board").GetComponent<Board>().isSwapping)
         {
             GameObject.Find ("Board").GetComponent<Board> ().SwapGems (this);
 
             //This will not allow us to click on any other objects while is swapping
             ToggleSelector ();
         }
 
     }
 #endif
 
 #if UNITY_ANDROID
     void Upate()
     {
          TouchDown();
     }
 
     //  OnTouchDown.cs
     //  Allows "OnMouseDown()" events to work on the iPhone.
     //  Attach to the main camera.
     void TouchDown()
     {
         RaycastHit hit = new RaycastHit ();
         for(int i = 0; i < Input.touchCount; ++i)
         {
             if(Input.GetTouch(i).phase.Equals(TouchPhase.Began))
             {
 
                 //Construct a ray from the current touch coordinates
                 Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(i).position);
                 if(Physics.Raycast(ray,out hit))
                 {
                     //if the state is in Motion then we can't click on other matches 
                     if (GameObject.Find ("Board").GetComponent<Board> ().DetermineBoardState())
                         return ;
                     
                     //This will ensure us that if the objects are swapping than we can't swap other objects.
                     if(!GameObject.Find ("Board").GetComponent<Board>().isSwapping)
                     {
                         GameObject.Find ("Board").GetComponent<Board> ().SwapGems (this);
                         
                         //This will not allow us to click on any other objects while is swapping
                         ToggleSelector ();
                     }
                 }
             }
         }    
     }
 
 #endif

As you can see I placed the macros that I want my function to be called for.

So, as I understood, When I will be in the Editor, my script will work with OnMouseDown.

But when I will be on Android, I will work with Update and TouchDown. Right ?

Reference from this link http://docs.unity3d.com/Manual/PlatformDependentCompilation.html

Than if that is true, why when Im building the Level for Android I'm getting this warning.?

Game scripts or other custom code contains OnMouse_ event handlers. Presence of such handlers might impact performance on handheld devices. UnityEditor.HostView:OnGUI()