Is Using Coroutines Actually Faster Than Update?

I've been doing a lot of research lately on how to increase performance of games on mobile and one piece of advice I came across was to use coroutines in place of Unity's built in Update function. It was mentioned on the forums that Update works closer to SendMessage than a standard function call, which causes more of an overhead. I'm very far into my project at this point so I wanted to get some data on the performance difference between Update and coroutines before overhauling my entire project. I created a blank project that has 1000 empty game objects running a simple update and 1000 empty game objects running the operation as a coroutine. The results were overwhelmingly in favor of Update, much to my surprise. Below are the two scripts used to test. Also attached below are the results of the profiler running on an original Motorola Droid. (It is worthwhile to note that this same project was tested on an iPhone 4 with almost identical results).

My best guess is the fact that System.Collections.Generic is not native to Android or iOS so Unity has to include it, which creates an overhead. Does anyone have any ideas why coroutines would be so much slower than Update?

Update:

 private int count;
 private float sine;
 
 // Update is called once per frame
 void Update () 
 {
     count++;
     sine = Mathf.Sin(count / 0.2F);
 }

Coroutine:

 private int count;
 private float sine;
 // Use this for initialization
 void Start () 
 {
     StartCoroutine(AddCount());
 }
 
 private IEnumerator AddCount()
 {
     while (true)
     {
         count++;
         sine = Mathf.Sin(count / 0.2F);
         yield return null;
     }
 }