A method for verifying the accuracy of a custody meter having a custody flow capacity with a displacement prover having a prover flow capacity includes providing a first master flow meter and a second master flow meter operating in parallel. The displacement prover is in series with the master flow meters and has a prover flow capacity that is less than the custody flow capacity. A fluid flow is diverted through the custody meter so that a portion of the fluid flow passes through each of the master flow meters. Each of the master flow meters are proved individually with the displacement prover. The custody meter is proved with both of the master flow meters operating simultaneously in parallel.