(3) A pharmacy benefit manager must establish a process by which a network pharmacy may appeal its reimbursement for a drug subject to predetermined reimbursement costs for multisource generic drugs. A network pharmacy may appeal a predetermined reimbursement cost for a multisource generic drug if the reimbursement for the drug is less than the net amount that the network pharmacy paid to the supplier of the drug. An appeal requested under this section must be completed within thirty calendar days of the pharmacy submitting the appeal. If after thirty days the network pharmacy has not received the decision on the appeal from the pharmacy benefit manager, then the appeal is considered denied. The pharmacy benefit manager shall uphold the appeal of a pharmacy with fewer than fifteen retail outlets, within the state of Washington, under its corporate umbrella if the pharmacy or pharmacist can demonstrate that it is unable to purchase a therapeutically equivalent interchangeable product from a supplier doing business in Washington at the pharmacy benefit manager's list price.