Book rate has changed over the years.  It used to be when Motor published
the data it had and advisory of time used by the average fully qualified
mechanic to complete the job at the vehicle or bench.  When I was in high
school and worked in shops it was the book plus .5 hours and another .5 hour
if it was a remove to bench job.  A carb job that needed to be removed and
taken to a bench that had to be prepped for the job was .5 hour for R/R plus
.5 plus .5 and then cleaned for .5 for a total two hours. And then the carb
tune and adjust charge which was a flat charge depending on type.  My actual
time on the job was about 1.25 hours before the tuning.  But the rest of the
charge actually went towards cleaning supplies and shop materials used for
the job.

That part is why many shops are now putting in a lot more use of a "shop"
charge.  This is usually around 25 dollars for cleaning supplies and shop
use materials that arent billed directly to a particular job.

At one of the shops I recently visited I liked a sign on his wall with
charges.
Not the exact wording but to the effect.

Cleaning charges. 
Major cleaning to safely repair or diagnose your vehicle problems $50
Cleaning beyond normal needed to complete a job properly $25
Charges are in addition to Shop fee of $25

While I was there the writer advised one vehicle operator that it would be
75 bucks to even bring the vehicle into the shop. I asked him after she left
and he said the engine was so dirty he couldn�t even tell which engine was
in the vehicle.  She was having electrical problems.  Wonder why???

These days I rarely challenge a shops charges but the dealer rates I have
definitely have confusion over.
jimt