Placing a Rect and detecting a Touch/Tap

Hi guys, I'm in the progress of creating my first 2D Game.

Since I'm both new to Unity and Android development I have some issues with Touch detection.

When I create a Rect with a height of 50px and a width of 100px, it seems as if the Rect is only registering Touch on the leftmost ~10px or so.

Here is my example code:

 using UnityEngine;
 using System.Collections;

 public class StartUpScript : MonoBehaviour {
 Rect buttonPLAY = new Rect(80, 340, 100, 50);
 
 // Use this for initialization
     void Start () {}
 
     // Update is called once per frame
     void Update () {
         if (Input.touchCount > 0) {
                 if (buttonPLAY.Contains(Input.GetTouch(0).position)) {
                 Application.LoadLevel("GameScreen");
                 }
                 
         }
 }

Also when it works, it feels kinda weird. As if he would fire events more than once or only if you press a certain amount of time. Is there another way to detect a single TAP anywhere on the specified Rect? As I understand it, "Update" is called once per frame. Might this be the problem?

Thanks for the help :)