Sounds like it was installed in something with low revs.
That said,Genghis Sr, now long retired, but once an engineering sales manager, once had to fire a sales rep whose mileagere-imbursement was based upon the odometer of his company car. Turned out the chap had disconnected the cable and connected it to a power drill to add miles, and thus income.
But six times, sounds more likely to be attached to something as already said, rotating around 500rpm. Kit gets used in all sorts of applications.
G