I work in aircraft maintenance and we sometimes give customers a quote for "Time and Materials" for a troubleshooting job, as opposed to a labor flat rate for something routine. If at the end of a 10 hour job we find that we missed something documented (or even something not explicitly documented but obvious, like missing bulbs) there's no way we would charge that 10 hours. That's poor practice, regardless of the open ended nature of the forms we require them to fill out before we even set foot on the aircraft. At my position I determine how long it
should have taken and charge accordingly.
In our case, our customers know way less about their aircraft than even the average person knows about their car. In fact, I could come up with a long description of the rabbit hole we went down and it's unlikely they could even Google anything because aircraft manuals are proprietary. In other words, even with no concern that a customer could coherently refute the excessive part of our charges we don't try and charge them. As a customer, even with an open-ended job, I am agreeing to pay you to
do the work not to
learn to do the work.
And I'm with
@Nuje, taking food off his table? Unless the service advisor and/or tech owns the shop (which they don't, because it's a dealer service center) the labor that customers pay is only tangentially tied to their pay. Everyone in my shop gets paid their hourly whether we are working aircraft efficiently, working them inefficiently, sweeping floors or doing "training" due to lack of work. Those that consistently work ineptly or inefficiently are encouraged and developed into better technicians and where that doesn't work they are let go or moved to a position they can perform.
If so many customers are rightly not paying for excessive labor hours spent doing the job incorrectly that a dealer service center (with it's captive customer base) closes that is a management failure. At that point, those involved have participated in a group effort to remove food from each other's tables.
Sorry for the rant, gets me mad.