Where does it say that it is estimated arrival time?... I see it as a time to reach a target at current speed... Which is what it is, no more, no less.
Thus, just keep it above 5 seconds and you'll not over shoot... It's not rocket science. Also, it's impossible to predict arrival time if you're not an autopilot because you could alter your speed at any time.
Seriously, if you get a bit of experience, you'll learn the drill... ah 45 seconds and 700 ls... that's about 3 minutes, then.
Thus, just keep it above 5 seconds and you'll not over shoot... It's not rocket science. Also, it's impossible to predict arrival time if you're not an autopilot because you could alter your speed at any time.
Seriously, if you get a bit of experience, you'll learn the drill... ah 45 seconds and 700 ls... that's about 3 minutes, then.