Does anyone have a script for Average Time of Day for 24hours?

Let's say you have "Start" and "End" fields, use this in 3rd field where you want to show average time as custom calculation script:

var start = this.getField("Start").valueAsString.split(":");
var end = this.getField("End").valueAsString.split(":");

if (start.length !== 2 || end.length !== 2) {
 event.value = "";} 
else {
 var meanMinutes = Math.floor(((+start[0] * 60 + +start[1]) + (+end[0] * 60 + +end[1])) / 2);
 event.value = ("0" + Math.floor(meanMinutes / 60)).slice(-2) + ":" + ("0" + (meanMinutes % 60)).slice(-2);}