4(4)Where the applicant and respondent in an application for child support or an application for the support of a child at or over the age of majority are not both parents of the child, sections 6, 7, 8, 9 and 10, subsection 15(2), sections 21, 22, 23, 24 and 25 and Schedules II and III of the Federal Guidelines, as adopted under section 3 of this Regulation, apply only to the extent necessary and reasonable to give effect to the spirit and intent of the provisions in the circumstances of the particular application and with such modifications as the circumstances require.