The discharge case length rate of a collector conveyor is controlled to provide a more consistent case length rate to the infeed of a downstream conveyor, such as a singulator conveyor, to control or maintain a desired case length rate at the exit of the collector conveyor without stopping the infeed conveyors. The discharge case feet rate accounts for the requirements of downstream devices, such as accounting for trailing gap requirements of a sortation conveyor disposed downstream of a singulator conveyor feed by a conveyor system constructed in accordance with this aspect of the present invention.