Live Flight Tracking

Hi,
I want to know how I can to get the minutes delayed for a flight?

I'm using the "FlightInfoEx" to get some information. I got the "filed_arrival_time" (calculated by filed_departure_time + filed_ete), the "actualarrivedtime" and the "estimatedarrivaltime"... and I don't know which one is the better option to know the minutes delayed...

Also have this question to understand a little more the API:
1) The "actualarrivaltime" is the real time that a flight arriva, right?
2) The "file_arrival_time" is the scheduled arrival time, right?
3) The "estimatedarrivaltime" is the arrival time calculated by the actual departure time, right?

Thanks!

actualarrivaltime is the time the flight actually arrived.
filed_departure_time + filed_ete is the time the flight was originally scheduled to arrive.
estimatedarrivaltime is an estimate of the arrival time, updated throughout the flight based on departure time and progress en route.