DekDee,
I wish I had a good answer for you on that, but I can't speak for the code. I should say that I also agree with your sentiments.
I can only go back to my earlier statement of not ever reviewing or writing a WPS without a listed chemical composition. I don't know where the connection is between that and a welder's ability to deposit a sound weld. Maybe there is an interpretation out there somewhere.
But, it goes without saying that the purpose of testing for chemistries on a CRO WPS is to ensure proper chemical ranges are achieved. Perhaps somebody with deep enough pockets convinced the committee that this is not always needed or required.
Either way, the deposited "t" must be listed on the WPS - it is an essential variable. Deposited "t" is determined using QW-462.5(a). The only way to do it properly is to do a macro etch. If someone with enough confidence or experience knows that proper chemical ranges are achieved with a certain thickness of "t", without performing a chemical analysis, maybe they can accept that. Therefore they could accept a groove weld qualification for a CRO qualification.
The devil is in the details; she also wears prada.