if i may add my 2 cents....
in the usa commercial / cfi and sic at 250 hours.
in argentina (where i started flight training)
commercial at 240, cfi at 500 and commercial
first class at 900. the commercial first is required
to work as co-pilot in the air transport service.
besides the 900 hours it also requires 25
hours of multi time and passing the atp written.
the atp is a check ride at 1500 hours.
i like the sliding scale aspect.
they get their commercial and then do sound
or banner towing, skydivers etc until they get
500 hours and do the cfi course.....