Re: recompense?
From the management point of view, it goes this way: neither the salesman nor the technician could have brought the deal in on their own merit, you need both.
Most technicians are willing to go the extra mile for the simple satisfaction of seeing the job well done.
Most salesmen are willing to go the extra mile only if they see a clear opportunity to bring home an huge amount of cash, while risking being left without anything if they don't go the extra mile.
So, wanting to minimize expenses and maximize earnings, you pay a standard salary to technicians and a percentage to salesmen.