When it's now 10 minutes away (data unchanged) you'll need to spend 30 seconds refreshing the screen to say that and then it'll be 9 minutes away. So they show

When it's now 10 minutes away (data unchanged) you'll need to spend 30 seconds refreshing the screen to say that and then it'll be 9 minutes away. So they show the time for 11 minutes instead of spending 30s of every minute refreshing the display.