The time it shows until the next departures for the lines will be wrong if you don´t update the list every 1min and that won´t work as you will exceed your API requests fast then.
So why not have the update every 5 minute that will work, and then let the JavaScript count down the time for you until the list is updated again from the API it may not be 100% correct but it will be alot more accurate then if you just let it be until the next update is made.
Edit: seems like i missed this part it the documentation
The time it shows until the next departures for the lines will be wrong if you don´t update the list every 1min and that won´t work as you will exceed your API requests fast then.
So why not have the update every 5 minute that will work, and then let the JavaScript count down the time for you until the list is updated again from the API it may not be 100% correct but it will be alot more accurate then if you just let it be until the next update is made.
Edit: seems like i missed this part it the documentation