Le tableau QW-256 de l'ASME IX 2007 précise que selon QW-410.25 la variable est nonessential
Le changement de méthode d'exécution dans la WPS ne remet pas en cause la PQR
If a change is made in any essential variable, requalification of the procedure is required.
If a change is made in a nonessential variable, the procedure need only be revised or amended to address the nonessential variable change.
Changes to the WPS.
Changes may be made in the nonessential variables of a WPS to suit production requirements without requalification provided such changes are documented with respect to the essential, nonessential, and, when required, supplementary essential variables for each process. This may be by amendment to the WPS or by use of a new WPS.
Changes in essential or supplementary essential (when required) variables require requalification of the WPS (new or additional PQRs to support the change in essential or supplementary essential variables).