tinpis - there were several!
The "Bypass Pay" system ensured you got payed for the type your seniority qualified you for if you were asked to stay back on the F.27. Hence some of the more senior F.27 checkers were actually being payed as B737 Check Captains while the management types were being paid as B727 Checkers.
If you listened carefully when engaging the starter, behind the great clunk of the solenoids engaging you could hear the "ker-ching!" of a cash register.
Is presume this is what you meant?