I'm afraid that might be asking for too much subtlety from the law. :)

It just says "children age 12 and younger may not be outside after 20:00 unless accompanied by an adult. Children ages 13 to 16 may not be outside after 22:00 unless they're returning home after an approved school-, athletic-, or youth-program function. Between may first and september first children may stay out an additional two hours"

Even though it's not stated the "accompanied by an adult" applies to ages 13 through 16 as well.