The additional amount prescribed in §41-22-203 shall be kept and reserved in a special fund for the use and benefit of the inmates so employed. This fund is to be reserved by the commissioner of correction and with the approval of the governor, to be used in making payments to deserving inmates, on a fair proportionate basis or to their dependents, in such sums and at such times as may be considered by the commissioner proper in order to reward good conduct, give the stimulus of hope to the inmates and best encourage them in discipline and efficiency.