GUI wrong movement? help

So heres the deal i got everything working in this script but theres one problem…
My gui moves not from down to up but from up to down
Heres script
Code

 var barDisplayH : float = 0;
var GUIskins : GUISkin;
var posH : Vector2 = new Vector2(20,40);
var sizeH : Vector2 = new Vector2(60,20);
var progressBarEmptyH : Texture2D;
var progressBarFullH : Texture2D;

var difference : float = 1;
var difference2 : float = 1;



function FixedUpdate() {

difference = (Screen.width / 12.8f) / 100;
difference2 = (Screen.height / 12.8f) / 100;

}


function OnGUI() {
GUI.skin = GUIskins;
GUI.BeginGroup (new Rect (posH.x*difference, posH.y*difference2, sizeH.x, sizeH.y));
        GUI.Box (Rect (0*difference,0*difference2, sizeH.x, sizeH.y),progressBarEmptyH);
        // draw the filled-in part:
        GUI.BeginGroup (new Rect (0*difference, 0*difference2, sizeH.x,barDisplayH * sizeH.y));
            GUI.Box (Rect (0*difference,0*difference2, sizeH.x, sizeH.y),progressBarFullH);
        GUI.EndGroup ();
    GUI.EndGroup ();
}

and maybe to get you know what im trying to do heres a picture
Picture

How to make it move from down to up?

Why dont you try inverting the values as in :

difference = -((Screen.width / 12.8f) / 100);
difference2 = -((Screen.height / 12.8f) / 100);

or just one of them if its getting the opposite of what you want.