Except for guardians ad litem appointed by the court from the subregistry created under RCW 26.12.177(2)(d), the court shall specify the hourly rate the guardian ad litem or investigator under this title may charge for his or her services, and shall specify the maximum amount the guardian ad litem or investigator under this title may charge without additional court review and approval. The court shall specify rates and fees in the order of appointment or at the earliest date the court is able to determine the appropriate rates and fees and prior to the guardian ad litem billing for his or her services. This section shall apply except as provided by local court rule.