(2) The board shall perform de novo review on the record. The board may address issues raised by evidence in the record, including but not limited to the nature of a separation, notwithstanding the scope of the issues raised by the parties, the arguments set forth in a party’s application for review or the parties’ written or oral arguments. The board may enter its own findings and conclusions or may adopt the findings and conclusions of the administrative law judge, or any part thereof. When there is evidence in the record both to make more probable and less probable the existence of any basic fact or inference, the board need not explain its decision to believe or rely on such evidence unless the administrative law judge has made an explicit credibility determination regarding the source of such facts or evidence. The board is not required to give any weight to implied credibility findings. The decision of the board shall become the final order unless a petition for judicial review is filed in accordance with ORS 657.282. [Amended by 1959 c.583 §18; 1965 c.210 §3; 1983 c.522 §2; 1985 c.404 §2; 1991 c.328 §1; 1993 c.344 §23; 1999 c.849 §125; 1999 c.1067 §7; 2003 c.75 §101; 2009 c.10 §2]