Public service companies and the petitioner seeking to establish or modify tariff rates for marine pilotage services bear the burden of proof in the general rate proceedings described in RCW 80.04.130 or 81.04.130. The burden of proof includes the burden of going forward with evidence and the burden of persuasion. The commission will consider the company's or petitioner's initial filing and any supplemental filings the commission authorized to be the company's or petitioner's full direct case in support of its rate change request for purposes of deciding any prehearing motion to dismiss under WAC 480-07-380.