(a) A person shall be a member under this Article if he or she (1) is or was employed and receiving a salary as a fireman under item (a) of Section 6-106, (2) has at least 5 years of service under this Article, (3) is employed in a position covered under Section 8-243, (4) made an election under Article 8 to not receive service credit or be a participant under that Article, and (5) made an election to participate under this Article.
     (b) For the purposes of determining employee and employer contributions under this Article, the employee and employer shall be responsible for any and all contributions otherwise required if the person was employed and receiving salary as a fireman under item (a) of Section 6-106.