Subject to the provisions of this section, a student who has completed at least 850 hours of training while enrolled in public school courses in barbering may practice barbering or provide barber–stylist services without a license. A student may practice barbering or provide barber–stylist services under this section only if the student: is enrolled in an approved barbering program and has a record of satisfactory school performance and school attendance, as determined by the local education agency; has a letter of authorization signed by the student’s teacher or work–study coordinator, to practice barbering or to provide barber–stylist services in a specific licensed barbershop; practices barbering or provides barber–stylist services only in that specific licensed barbershop; and while practicing barbering or providing barber–stylist services, works under the direct supervision of an individual who is a licensed master barber who agrees to periodically report on the progress of the student to the barbering teacher or the work–study coordinator. Under this section, there may not be more than three students working under the supervision of a licensed master barber. A barbershop may pay a student for work authorized under this section. A student authorized under this section to practice barbering or to provide barber–stylist services without a license shall conspicuously display a letter of authorization, as required by this section, at the student’s work station in the specified licensed barbershop.