a. Producer/Producer - When one or more producers sell or utilize a volume of natural gas in excess of their gross working interest. b. Pipeline/Pipeline - When a pipeline receives a volume of natural gas and redelivers a larger or smaller volume of natural gas under the terms of a transportation agreement. c. Producer/Pipeline - When a producer delivers a volume of natural gas that is larger or smaller than the volume of natural gas that the pipeline redelivers for the producer's account to another party.