They would prefer not to keep costs down since they don't get rewarded for it, they get their budget cut for the following year. A conceivable approach to keep cost down is enable them to keep the sum they didn't save and put it into a saving account and enable that agency to gain interest on it. Also, at regular intervals there would be a reevaluation of funds required by agencies; if their budget grows or gets cut they keep the saving account until the point when it is expended.
