PIWA Coefficient: Addendum v1.1 Supersession Notice — April 20, 2026 Supply Chain Discontinuity

This addendum formally notes that the PIWA Coefficient as formulated in v1.0 BETA is superseded as of approximately 20 April 2026. Three concurrent eventsinvalidate the clean proxy assumptions on which the model depends: (1) the arrival of the final Gulf Oil shipments sourced via Hormuz-adjacent supply chains, afterwhich PNZ91 ceases to function as an unfiltered seismograph of Strait of Hormuz throughput; (2) the NZ Government’s In-Work Tax Credit (IWTC) interventionintroducing a demand-side subsidy that partially masks the retail price signal; and (3) the shelving of the planned 12-cent fuel excise increase, removing an anticipatedupward shock from the domestic price series. Critically, the model’s core resolution threshold (τ = $3.50 NZD/L) has already been breached as of mid-April 2026,placing the PIWA coefficient formally at or above 1.0. The theory is therefore closed on its own terms: the predicted pain-equilibrium condition is confirmed. Futuremodelling will require recalibration against alternative-market supply chains (AU,SE Asia) rather than direct Gulf pricing transmission.