These two features ensure that a large minority can fund several agencies regardless of what the majority gives those agencies. But the danger of a rep dumping all her funds on a favorite necessitates an incentive to distribute funds. Each rep also has only a limited number of political chips or influence points needed to push her grants away from neutral. No points are charged for a neutral grant. There are equal charges for lowering as well as raising budgets.
Voters pushing in either direction have no advantage over their opponents.
Chip costs rise sharply if a rep drops her grant near zero. To zero out an agency is the budgetary complement of dumping funds on a favorite and not supporting the other public goods one uses. The cost schedule also soars as a grant nears double the neutral level. So the practical upper limit for a grant is about 2.0 times the neutral grant. Incentive systems are only as good as the behavior they evoke.