This is a recent hot button issue with ASME and National Board. Team Leaders are wanting to see evidence of how the "A" number was determined by the Certificate Holder. For GMAW welding, QW-404.5 requires a chemical analysis of the qualification weld to determine A Number. There are a couple of other options as well. You can always list E 70C-6M-H4 under "A" number on the WPS, but you will be limited to that filler metal. Lincoln also provides certificates of weld metal analysis of filler metal/gas combinations. That is also acceptable. The AIA's should be asking these questions of the Certificate Holders before they get burned during a joint review.