Two lerps in the same loop, but one takes longer, why?

I'm doing two lerps simultaneously, one for centering the camera, other for zooming, using this code:

IEnumerator centerCameraAndZoom(Vector2 source, Vector2 target, float duration, float zoomAmount) {

 float t = 0;
 while (t < 1) {

     // add the time
     t += Time.deltaTime / duration;

     // smooth it out (easing)
     var lerped = Mathf.SmoothStep(0.0f, 1.0f, t);

     // zoom in
     Camera.main.orthographicSize = Mathf.Lerp(Camera.main.orthographicSize, zoomAmount, lerped);

     // move canvas center in the direction of the card
     canvas.GetComponent<RectTransform>().anchoredPosition = Vector2.Lerp(source, target, lerped);


     yield return null;
 }

} My problem is that, even though both are theorecitally lerping for the same speed (t is the same for both), the motion of the canvas center takes much longer, resulting on a delayed moving after zoom is done.

Any ideas on how to deal with this, while still keeping the code inside of a single loop?