Oregon Revised Statutes Property Rights and Transactions § 90.160

(1) Notwithstanding ORCP 10 and not including the seven-day and four-day waiting periods provided in ORS 90.394, where there are references in this chapter to periods and notices based on a number of days, those days shall be calculated by consecutive calendar days, not including the initial day of service, but including the last day until 11:59 p.m. Where there are references in this chapter to periods or notices based on a number of hours, those hours shall be calculated in consecutive clock hours, beginning immediately upon service.

(2) Notwithstanding subsection (1) of this section, for 72-hour or 144-hour nonpayment notices under ORS 90.394 that are served pursuant to ORS 90.155 (1)(c), the time period described in subsection (1) of this section begins at 11:59 p.m. the day the notice is both mailed and attached to the premises. The time period shall end 72 hours or 144 hours, as the case may be, after the time started to run at 11:59 p.m.