You don't have the perspective of the courier. Goals are set, whether by manager or ROADS,
ROADS doesn't set goals.
there is no change in the route, but simply because the courier can meet or exceed those goals, they are raised until they can no longer be met.
If a courier is consistently exceeding the goal, then the goal is too low.
Then the courier is harassed because a swing, who ignores Best Practices, can meet them. Does that mean they are attainable? Yes, but at the expense of safety. Then "safety" becomes lip service by Corporate. This is the number 1 complaint from couriers, and P-S-P becomes hogwash. Nothing you can say can spin it into something legitimate and logical.
You're going with the assumption that swings who nuke goals aren't working safely. If you're a courier whose route was smoked by a swing, go to you manager and explain which practices he did that were unsafe.
Here's an example of what I've usually found. Sixty stop route. Courier missing his goal by 25 minutes. "I'm doing the best I can." Spends about a minute talking at most of his business stops. Stops at a gas station for a drink and a snack - 3 minutes. Spends 10 minutes looking for packages, working around poorly sorted packages, and re-sorting them. Breaks route to deliver an afternoon stop as early as he can because it's for his buddy/he has a crush on the receptionist/whatever and he wants to take care of him/her - 5 minutes out of the way.
Right there you have 18 minutes of time that he's wasting (plus his chit-chat time at some stops) from a guy who's doing the best he can, or so he says. This is an easy fix.
I push him to do a better job of sorting his truck because that reduces a 25 minute issue to a 15 minute issue. If he does that and cuts an average of 20 seconds from each stop, he's beating his goal. He can cut that 20 seconds just by walking at a brisker pace (and he can also cut out some of the other stuff I listed). "Sort your truck better and give us just a few seconds at each stop and you're in the clear." It's my opinion that you fix the most egregious deficiency and ask for however many seconds per stop to make up the rest.
In this scenario he still gets to do the things he likes, his work isn't being nitpicked, he's only being asked to fix one deficiency, and he's not being asked to do a lot in order to close the gap.
It's fairer to the courier that way and most seemed to appreciate having it presented in that manner.