In short, delays are totally dynamic & there is no real effort to control them.
Well Said... But from which end... You mention slot times to airline execs and they cringe... Probably because the way things have gone in the past every attempt to reduce/save/add efficiency has been f'cked up because of some penny pinching process that ASA tried to implement as 'good enough' instead of being resourced properly... What exactly is the NOC doing? Was/Is it a good investment? If it is a good investment, for who?