(a) A GAL appointed by the court and to be paid by public funds shall be paid in accordance with law or rule and shall not seek or receive any additional payment from any party.

    (b) The parties may agree upon a certified GAL to be appointed by the court and may agree to a private fee different from that provided by court rule or law. Where a private fee arrangement different from that provided by court rule or law is agreed upon, the GAL shall:

        (1) execute a written fee agreement with the parties which designates the party responsible for payment or that the designation may be made by the court and that the court's order relative to payment shall take precedence over the agreement; and

        (2) not enter into any contingent fee agreement.

    (c) A GAL shall submit itemized statements as ordered by the court.