Let assume a), b) and c) are three different pipelines, from the gathering lines to the storage tanks. The pipeline a) would be an example of one without AOTs. The pipeline c) would be an example of a pipeline with AOTs.
As far as b) is concerned, try this: take a standard 5/8-inch diameter water hose, cut it in two. Using 5/8-inch to 1-inch adapters, install a 5 foot length of 1 inch hose in the middle. Run the water through it. The water entering the hose will have the same velocity as the water leaving the other end (same flow rate). All that work for nothing.