IOS touch vs OnMouseDown & error messages

Hey Guys, Currently i have an ios project that uses all OnMouseDown methods instead of specifically touch inputs methods, it seems to work fine and i can test it on the computer and on my iphone. It works great but when i go to build it i get the warning: Game scripts or other custom code contains OnMouse_ event handlers. Presence of such handlers might impact performance on handheld devices. UnityEditor.HostView:OnGUI()

This is an example of a raycast im using:

     void Update(){
         if (Input.GetMouseButtonDown(0)){
             Ray ray = camera.ScreenPointToRay(Input.mousePosition);
             RaycastHit hit;
             if (Physics.Raycast(ray, out hit)){
                 objectRayHit = hit.collider.gameObject;
 
                 if (objectRayHit.name == "1OrangeCube" && DataManagement.datamanagement.playerSuitColor != 1){
                     DataManagement.datamanagement.playerSuitColor = 1;
                 }

and this is an example image of the scene im using this in:

Why am i getting this error? my game is a very simple game and it seems to work fine but obviously i want to release it with the best coding i can muster. Any help will be greatly appreciated.

There is a similar unanswered question here: http://answers.unity3d.com/questions/669282/performance-impact-of-onmouse-event-handlers-on-mo.html