Refers to the comparability of quantity and quality of firm transportation service offered to the pipeline's firm bundled sales service. Aspects of comparability include access to storage and production area facilities, flexibility of receipt and delivery points, balancing requirements and other terms and conditions of service. There must be sufficient comparability of service, as well as DIVERTIBLE GAS SUPPLIES, in order to determine that a pipeline's market is competitive as firm transportation cannot be a viable alternative to the pipeline's sales service if transportation service is not comparable. The Commission has found that one way of enhancing comparability is for customers to convert all of their sales entitlements to firm transportation and for the point of sale from the pipeline to be moved upstream to the wellhead or to a HEADSTATION. In this way, all gas on the mainline is transportation gas.