“21. In computing the grants contemplated in sections 14.4 and 17.4, however, no account shall be taken of pupils for whom a school corporation assumes the tuition fees under an agreement entered into, according to section 262 of the Act respecting public elementary and secondary education (chapter E-8.1), or of pupils who are the object of a contract for services contemplated in section 67 of this Act or of pupils registered for a self-improvement course.”.