Section 803.405 - Effect of initial registration month(1) The month in which any vehicle is initially registered under annual registration is the month established as the beginning and ending of registration periods for the vehicle unless the Department of Transportation adjusts the registration month of the vehicle upon initial registration under ORS 803.410.(2) The day on which any vehicle is initially registered under biennial registration or when required under ORS 820.520 is the day established as the beginning and ending of registration periods for the vehicle unless the department adjusts the registration period of the vehicle upon initial registration under ORS 803.410. 1983 c.338 §223; 1989 c.76 §2