After a hearing an appeal tribunal shall promptly make findings and conclusions and on the basis of them shall affirm, modify, or reverse the determination. Each party shall be promptly given a copy of the decision, the supporting findings, and the conclusions. This decision is final unless further review is initiated under AS 23.20.435 within 30 days after the decision is mailed to each party at the party's last address of record or delivered to the party. The period within which further review may be initiated may be extended for a reasonable period of time upon a showing that the application was delayed as a result of circumstances beyond the party's control.