(1) Every affected incorporated city, municipality and fire district shall put into effect and maintain a schedule of working hours required of regularly employed firefighters which shall not be in excess of the average hours established by ORS 652.060, and which shall provide for at least 48 consecutive hours off-duty time in each seven-day period. Any affected incorporated city, municipality or fire district failing so to do shall pay to every regularly employed firefighter as additional pay for every hour of regular duty required of and performed by the firefighter over and above the average hours established by ORS 652.060 a sum equivalent to one and one-half times the regular hourly rate of pay at the time of such default. However, in the case of replacement for any authorized leave, vacation or temporary vacancy, regularly employed firefighters in a department employing four or more persons on a full-time basis as firefighters may elect to work in excess of 56 hours a week at not less than their regular hourly rate of pay.
(2) Nothing in subsection (1) of this section requires payment of one and one-half times the hourly rate of pay to a volunteer firefighter for hours of duty performed in excess of the average hours established by ORS 652.060.