A sales rep is not middle management.
The people in the warehouse don't report to Stanley. His job is to get sales from customers. He has no one reporting to him.
Michael is the chief clueless person in the show. Dwight and Andy are aspiring clueless.
The losers are the people who do the day-to-day work that keeps the company in business. The sociopaths are the people at the top who view the company as a board game with pawns that can be moved around or sacrificed at will.
The purpose of the clueless is to put a buffer between the sociopaths and the losers so that the sociopaths don't have to consider that their pawns are real people with real feelings and real families to take care of.
There are three classes of losers according to his system:
1. Over-performing losers, who are prime candidates for promotion to the clueless ranks
2. Average losers, who know they have a raw deal but don't have the ambition or coldness to do anything about it.
3. Under-performing losers, who are prime sociopath candidates because they have a lack of "give a damn" about what they do and are willing to push the boundaries because they know the deal is not in their favor.
Note that the over-under here is relative to ability. Jim is an under-performing loser, while still being very good at his job, because he doesn't put in his best effort.
Kevin is an average loser because even though he's not that good at his job, he's giving a good-faith effort to what he does.
Dwight is over-performing because he's always attempting to go above and beyond, even when it is inconvenient to him.