For purposes of ORS 164.345, 164.354 and 164.365, the value of damage done during single incidents of criminal mischief may be added together if the incidents of criminal mischief were committed:
(1) Against multiple victims in the same course of conduct; or
(2) Against the same victim, or two or more persons who are joint owners, within a 30-day period. [1999 c.1040 §12]