(1) Any person, firm, corporation, association, political subdivision, department of the state, or agency, subdivision, or instrumentality of the United States employing a person owing a support debt or obligation, shall honor, according to its terms, a duly executed assignment of earnings presented by the secretary as a plan to satisfy or retire a support debt or obligation. This requirement to honor the assignment of earnings and the assignment of earnings itself shall be applicable whether said earnings are to be paid presently or in the future and shall continue in force and effect until released in writing by the secretary. Payment of moneys pursuant to an assignment of earnings presented by the secretary shall serve as full acquittance under any contract of employment. A person, firm, corporation, association, political subdivision, department of the state, or agency, subdivision, or instrumentality of the United States that complies with the assignment of earnings under this chapter is not civilly liable to the debtor for complying with the assignment of earnings under this chapter. The secretary shall be released from liability for improper receipt of moneys under an assignment of earnings upon return of any moneys so received.

(2) An assignment of earnings presented by the secretary in accordance with this section must include income withholding forms adopted and required by the United States department of health and human services.

(3) An assignment of earnings presented by the secretary in accordance with this section has priority over any other wage assignment, garnishment, attachment, or other legal process except for another wage assignment, garnishment, attachment, or other legal process for support moneys.

(4) The employer may deduct a processing fee from the remainder of the debtor's earnings, even if the remainder would be exempt under RCW 74.20A.090. The processing fee shall not exceed fifteen dollars from the first disbursement to the department and one dollar for each subsequent disbursement under the assignment of earnings.