Ahhh, wouldn't you know it. The current Certification notes under the CWI testing schedule shows that as of Nov 29, 2008, there is an endorsement for D1.2. This shouldn't make any difference to the answers you've received here though. Unless its in the contract documents, neither AWS or ASME specifies who may or what level of training is required to write a WPS. My company, for instance, which is an OEM for oil field solutions, requires that a welding engineer be included in the procedure development for sales purposes. What that has evolved into is I plan and write the WPS, do the observation for the PQR recording all the data, specify and send the sample off for mechanical testing, then write the whole thing up and send it to the welding engineer to accept or not as a contracted reviewer. As far as the code books are concerned a dog, three ducks, and chicken could do my part if they could do it correctly.