In Boone v. Boone, 960 P.2d 579 (Alaska 998), the Supreme Court of Alaska required its lower court to make such a justification. Its rules permitted retroactive application of a support order from the date the motion was served on the opposing party. The text of Alaska's rule expressed no preference or presumption that modification become effective on the date of service, nor did it limit that lower court's discretion in selecting a later date. Boone, 960 P.2d at 585. However, the court in Bonne established a preference for the earlier date and imposed upon lower courts the requirement that they make findings before selecting any later effective date. Id. The reasoning was that "delays in resolving such disputes should not disadvantage parties entitled to relief." Id. In addition, "the needs of the children, upon which the court focuses in determining whether a substantial change of circumstance has occurred, are examined as of the date the petition is filed." Id.