(1) To the extent possible, child support orders must address children's changing needs as they grow and mature in a way that minimizes the need for future modifications. If any material change in current circumstances is anticipated within 18 months, separate child support calculations must be completed.

(2) In the initial calculation, present circumstances should be included. In the subsequent calculation(s), appropriate anticipated changes should be calculated. The child support order should provide that the amount(s) from the subsequent calculations will take effect the month following the anticipated changes.