I've got a copy of the SoCal contract for Needles.  The exact wording for the pressure requirement is:

SECTION 5. PRESSURE. 

Seller shall tender gas to Buyer, at the delivery point on the California/Arizona border near Needles, California, at a pressure of not less than 750 PSIG, and not more than 1000 psiq, with an anticipated nominal operating pressure of approximately 800 psig, unless otherwise mutually agreed by the parties. For purposes of this Service Agreement, pressure at the delivery point shall be calculated from actual readings at Seller's Needles measurement facility utilising generally accepted engineering formulas designed to calculate a pressure drop over a given distance of pipeline, gravity, temperature, and flow rate and other variables as may be reasonably necessary to make such computation, and may be confirmed by calculations at Buyer's North Needles Compressor station. 

It is my interpretation that our pressure requirement occurs exactly at the California/Arizona state line and we can use modeling methods to determine the required outlet pressure at the Needles station required to achieve 800 psig at the state line.