Over/under is utter BS. Some routes you can run, and I mean literally run, as fast as you can, work through lunch, skip breaks, with the least miles possible and still be "over". Some routes you can stroll through, take all breaks and lunch and come in "under". Complete and utter BS.
It's hard to believe the union still accepts "bonus" as a legit thing in some places. So much room for unfairness and favortism with the faulty algorithms they use.
"Favorable" routes pay more for less work whilst "unfavorable" routes pay less for more work. Certainly not an equitable arrangement imo.