Laptime timer using TimeSpan - force milliseconds to 00 and not 000?

Hey guys, I'm using TimeSpan for a laptime timer in my racing game, which works great...but there's 1 little hiccup I can't seem to figure out, and that's for the Milliseconds section of the timer, which is always in this format: 000, and I want to force it to be: 00 instead.

Here's my code below:

 private GUIText laptime;
 
 void LateUpdate ()
 {    
     // "timer" is being calculated in EventManager like this:
     // timer = (Mathf.Round((Time.time - startTime) * 100.0f) / 100.0f);
     laptime.text = "Laptime : " + SetTimeSpan( EventManager.timer );
 }
                   
 public static string SetTimeSpan( float time )
 {    
     // Create TimeSpan variable
     System.TimeSpan timeSpan = System.TimeSpan.FromSeconds( time );
     return string.Format( "{0:D2}:{1:D2}:{2:00}", timeSpan.Minutes, timeSpan.Seconds, timeSpan.Milliseconds );
 
 }

Is there a better way to create this type of timer? And how can I force it to always be in this format: 00:00:00 instead of 00:00:000?

Thanks for your time! Stephane