Originally Posted by
Lux Flyer
It's so weird what happens when you focus isn't overwhelmingly D0 as the be-all-end-all (AA). For some reason you can still get flights arriving on time and more of your customer's get to where they want to be sooner, by making sensible swaps like they did in OP's situation.
The goal is to arrive on time. Leaving on time helps with that goal, but that's not the best metric to be obsessed with.