I had a similar experience as you, betterfasterstronger, and might be able to offer a solution in the form of a lengthy autobiographical anecdote. Call it a millenial response.
About two years ago, I was newly hired and recognized for my work ethic and performance (12-2000pph, no missorts) etc. learned all the jobs blahblah and usually switched between unload and sort. i.e. worked like crazy. It wasn't a matter of money-per-calorie or fair day's anything for anything; it was the best of my ability, all the time, doing anything, for any or no reward. I'm not puffing my chest or putting down people who don't do this. It's an empirically stupid and vain way of conducting one's affairs. Flat. However, I feel as though you can relate to this sort of motivation more than to some of the other more 'biological imperative' geared responses.
Anyway, when in the sort aisle I would always be put on the heaviest slide, usually by myself. (Hard work earns more hard work, as I'm sure you're aware of by now.) After weeks of waking up with my knuckles locked painfully at 90 degrees I requested I not be put on the slide (which is the equivalent of sorting 2-3 people
on top of your assigned sorter) every day, and after getting answers like I should enjoy it because it's a challenge (which was really to say nobody else was willing to do it, though I did enjoy the challenge), I told my supervisor that if, the next day, I was assigned the slide, I would deliberately fail to work as directed because it would be a direct hazard to my health, and further I would seek a permanent transfer to the unload if I was not given at least one or two days off the slide per week, which is about the frequency at which I actually do the slide now. I got more than what I wanted. What's more is during those weeks I made a note of all the sorters who went out of their way to help me, and those who didn't. Those who didn't get little from me today.
Supervisors are told to take advantage of high performers, and the more minimalist work ethics will naturally ride your coattails, but high performers don't often enough use their value as leverage because of the culture of intimidation and subordination fostered at UPS. Supervisors have to put on a front like you are more losable than you are a commodity, but this isn't the case. The truth is Brown gets a ton of new hires every single week, and/because most of them are pure chaff and get fired or quit the same week. People like you don't come around very often, and when you do, supes are torn between milking you for everything you've got and risking you quitting. It's like landing a date who's too pretty for them and overcompensating by being a jerk. Supervisors, however, will go out of their way to prevent more chaff from being pumped through their area, but they need a gentle reminder of the limits of their good fortune. Gentle. Don't strut like you're big mister cheese or fail to work as directed or refuse to help someone, just let it be known you are, in fact, a losable commodity and make a note of coworkers who take advantage of you. Then cut the cord when doable without risking termination. I've failed to work as directed, arms crossed, and got what I wanted. I don't suggest you be so bold, but you have more power than you are led to believe you do, and it doesn't require not working as hard as I'm sure a Marine always wants to in order to use it.
The key thing to remember for UPS is that performance does not make you a superman, your attitude does. Be a superman in more ways than physical and you will most likely get at least some of what you want. Make no mistake, you'll still get most of the smile* you don't want because of lazy or senior coworkers, but you'll get more benefits. For instance, my unload supervisor usually gave me an extra fifteen or twenty minutes over my punch out time whenever I unloaded. (Something about needing two sorters
). I still got stuck in crap loads, but I got some extra $ for it.