3Where the qualifying period of pensionable service performed by a scheme member is less than 37 years, the rate of pension in respect of the whole-time service shall be calculated by adding together for each complete year of pensionable whole-time service 1/37th of the pension to which he would have been entitled under the foregoing provisions of this Schedule if he had performed 37 years' whole-time pensionable service; and where the whole-time pensionable service comprises a broken part of a year the rate shall be increased by adding, in respect of each complete month in the broken part, 1/12th of the amount payable in respect of a complete year.