An obligor may execute a document voluntarily authorizing income withholding from current or future income due the obligor from an income payer in an amount sufficient to meet any child     support obligation imposed by a court or otherwise. An income withholding authorization made under this section is binding on the income payer one week after service upon the income payer by first-class mail, or in any other manner agreed to by the income payer, of a true copy of the executed income withholding authorization. The income payer shall deduct the sum or sums specified and pay them as specified by the income withholding authorization and any applicable imposition of a support obligation by a court. In addition, the income payer may deduct a fee of three dollars per month from the obligor’s income to cover expenses involved in transmitting payment. Compliance by an income payer with an income withholding authorization issued under this section discharges the income payer’s liability to the obligor for that portion of the obligor’s income. The income payer may not use the income withholding authorization as a basis for any disciplinary action against the obligor.