Some of my contacts show up as "away" all the time. I know for a fact that some are indeed away from their computer, and have the idle status either disabled, or enabled for the maximum time.

Is there any way to override this and see when a contact is actually away from their computer, and for how long?

if they show as "away" and have idle set to the maximum time (or disabled)....then they have just set their status to "away".....that's all there is to it

there is no way to override a status and tell whether someone is there or not as it would be an invasion of privacy.  plenty of people i know have their status set to "away" or "busy" regardless of their real status......the easiest way is to talk to them and see if they reply......if they don't reply then either they're not there, or they don't want to talk to you