(a) Anything in this act to the contrary notwithstanding and except as otherwise provided in this section, any employe of such cities or paid out of the city treasuries thereof, in active service on or after the effective date of this act, who is a contributor to and member of the pension fund of such cities, may elect to receive and shall be paid a lesser pension during his lifetime, if and when he meets the requirements of this section. Such election shall be made by application to the board of pensions.

(b) Every employe in active service on or after the effective date of this act who is dismissed, voluntarily retired, or in any manner deprived of his position or employment, with fifteen years or more but less than twenty years of service and who has contributed to the pension fund for a like period and who has reached the age of sixty years or upwards, may apply for such lesser pension.

(c) Every employe in active service on or after the effective date of this act who is dismissed voluntarily retired, or in any manner deprived of his position or employment after fifteen years or more but less than twenty years of service before attaining the age of sixty years, upon continuing until he reaches the age of sixty years a monthly payment to the fund equal to the last amount due and paid monthly while in active service, may apply for such lesser pension when he reaches the age of sixty years.

(d) Every such lesser pension shall be proportionate to the pension which the employe would be entitled to receive after twenty years of service and contribution, computed as if he had continued to receive, during the remainder of the twenty years, the average rate of pay at which he was employed during the highest salaried five years of his active service as his number of months of service is to two hundred forty months.

(e) Payment of the monthly amount of contribution shall cease and be discontinued at the time any such employe begins to receive the lesser pension provided by this section.