The Commission addressed the backhaul issue in Order Nos. 637-A and 637-B.
Bottom line is that backhaul and forward haul cannot overlap.
However, new development is full CD forward haul and full CD backhaul can be delivered at same point.

Here is what the Commission said in Order No. 637-A:

EXAMPLE:

Points:  M	A	N	O	P	Q	R	B			S
_______________________________________________________________________________________

		>>>>10,000 FORWARD>>>>>>>>>>>>>>>>>>><<<10,000 BACKHAUL<

	"Both the releasing and replace shippers also would retain the flexibility to use their capacity fully to make backhauls.  Thus, the shipper could deliver 10,000 Dth from point A to Point B using forward haul capacity and 10,000 Dth from point S to point B using a backhaul, because there is no overlap over the mainline.
	This may require a change by some pipeline with respect to their tariffs regarding backhauls.  The Commission's policy on the use of forwardhauls and backhauls to the same pont in excess of contract demand has been in the process of change.  While the Commission found in 1997 that a shipper cannot use the same delivery point for a forwardhaul and backhaul in excess of contract demand, the Commission recently found that a forwardhaul and backhaul to a series of 23 meter station considered as a single point for nomination purposes did not result in a capacity overlap even though the total amount received by the shipper exceeded contract demand.  In order to promote shippers' ability to use their capacity as flexibly as possible, the Commission has determined that prior restrictions on shippers' use of forwardhauls and backhauls to the same point should not be followed.  Shippers' segmentation right should not depend on metaphysical distinctions between delivery to a single point or to two points adjacent to each other.  In both situations, shippers should be permitted to use a forwardhaul and a backhaul to deliver gas as long as the mainline contract demand is not exceeded and they can take delivery of the gas."  (Footnotes omitted.)

In Order No. 637-B, the Commission addressed requests of INGAA, Williams and the El Paso pipelines for rehearing of this very point. The Commission denied rehearing, repeating much of what it had said in Order No. 637-A.


NOTE:  Seems like there is more than a "metaphysical" difference between deliveries to a single point versus two points.  However, the Commission does recognize that there may be a physical constraint, and maybe even a scheduling constraint.