This chapter shall not apply to or affect in any manner courses of instruction offered in high schools, vocational-technical schools, colleges, or universities which are now or hereafter established, nor shall it be applicable to instructors in any such high schools, vocational-technical schools, colleges, or universities: PROVIDED, That such course or courses are conducted by such schools in a like manner to their other regular courses. If such course is conducted by any commercial school as herein identified on a contractual basis, such school and instructors must qualify under this chapter.