QW-405.1, 2 and 3 could apply. QW-405.2 applies ONLY if notch toughness is required (which would be unlikely in the case of stainless steels). The other 2 variables, QW-405.1 and QW405.3 are NON-ESSENTIAL variable for procedure qualifications. Your Customer may have some point he wishes clarified but rejectting the WPS seems a bit harsh.