The department shall determine and fix reasonable hours of employment for minors under 16 years of age in street trades. Except as provided in this section, the department may not fix hours of employment for minors under 16 years of age in street trades that exceed the maximum hours per day and per week specified in s. 103.68 (2) (a) and (b), that exceed the maximum days per week specified in s. 103.68 (2) (c), or that begin earlier or end later than the hours specified in s. 103.68 (2) (d) and (e). The department may not limit the hours of employment for minors 16 years of age or over in street trades or the hours of employment for minors of any age who are engaged in the delivery of newspapers to the consumer.