If the client is qualifying welders for GMAW-S and they are working to D1.1, they have to qualify a procedure. If the welders are qualified, but there's no qualified procedure to use for fabrication, the welder quals are meaningless. A WPS qualified by testing isn't typically transferable to another organization/company. That is, unless they purchase a license to use the standard WPSs sold by AWS. All very convenient wouldn't you say?
Best regards - Al