1. Notwithstanding any other provision of law to the contrary, whenever a parent in emergency military service has a change in income due to such military service, such change in income shall be considered a change in circumstances so substantial and continuing as to make the terms of any order or judgment for child support or visitation unreasonable.

2. Upon receipt of a notarized letter from the commanding officer of a noncustodial parent in emergency military service which contains the date of the commencement of emergency military service and the compensation of the parent in emergency military service, the director of the family support division shall take appropriate action to seek modification of the order or judgment of child support in accordance with the guidelines and criteria set forth in section 452.340 and applicable supreme court rules. Such notification to the director shall constitute an application for services under section 454.425.

3. Upon return from emergency military service the parent shall notify the director of the family support division who shall take appropriate action to seek modification of the order or judgment of child support in accordance with the guidelines and criteria set forth in section 452.340 and applicable supreme court rules. Such notification to the director shall constitute an application for services under section 454.425.

4. As used in this section, the term “emergency military service” means that the parent is a member of a reserve unit or National Guard unit which is called into active military duty for a period of more than thirty days.