In case of a dispute over the amount of a water rent bill, or over the accuracy of a meter, the Water Superintendent shall, at the request of the consumer, test the meter. If it is found upon such test, that the meter registers a greater amount of water than has actually passed through it, the City Collector shall thereupon adjust such bill to conform to the correct amount due from the consumer, as nearly as the same can be ascertained, and for making such test, said Collector shall collect the sum of fifteen dollar ($15.00) as the cost thereof, except in cases where the meter was furnished by the City. If, upon making such test, said meter shall be found to register correctly, or registering a less amount of water than has actually passed through it, the consumer will be required to pay the correct amount due, as nearly as the same can be ascertained, and in addition shall pay the sum of fifteen dollars ($15.00) for the costs of making such test.