Inaccurate WorldToScreenPoint

Hello everyone.

I am trying to make a web-player orthographic 2d game and ended up with a strange problem. For some reason despite both the object and the camera both starting at (0,0) my y value is incorrect. My game resolution is 795x530 yet the y value reported is 252.28. That's 12.72 off. Even more strangely, the X co-ordinate is correct.

 void Update () {
     Vector3 pennyVecPixtemp = Camera.main.WorldToScreenPoint(transform.position);
     pennyVecPix.Set (pennyVecPixtemp.x, pennyVecPixtemp.y);
     sX = Camera.main.pixelWidth;
     }

Does anyone have any ideas?