(1) Service credit earned by part-paid firefighters prior to July 1, 1981, will be computed and granted on the basis of the ratio of salary earned by the part-paid firefighter to the salary paid to a newly confirmed full-paid firefighter during the same time period.

(2) Service credit earned on or after July 1, 1981, shall be granted under the assumption that all part-paid firefighters work 15% time. Employer and part-paid employee contributions to FURS will be based on an assumed salary for part-paid firefighters which is 15% of a newly confirmed full-paid firefighter's salary for the same time period.

(3) A part-paid firefighter will accrue service credit of one month for each calendar month during which contributions are made; however, if and when the part-paid service is qualified into another system, or if the part-paid firefighter also has full-paid firefighter service credit, each calendar month of part-paid service shall be credited as only .15 months of service.