Marty,
I won't often step into a disagreement with you on Section IX, but I'm not sure you are correct here. I'm actually proposing a theoretical based upon this post but not in answer to it necesarily since as you stated the tensiles are good in any case if they broke in the BM.
In any case, unless you have an Interpretation available it could be argued (and I'm not 100% behind this though I'm getting there) that dual certification does not have to be considered for procedure qualification acceptance criteria in that the MTR is stating you have essentially both 316 AND 316L. Section IX does not say you have to comply with the material cert, it says you have to comply with QW-422. The material cert only identifies and verifies what you have. QW-422 says 316L is required to have 70ksi T(without looking it up). You have a material that is 316L and the low tensiles of a PQR (say 69ksi in the base metal) comply with that requirement.
The reason I put it this way is that if you had this situation all you would have to do is have the manufacturer remove the 316 statement on the MTR and you would then have a good PQR although nothing has changed except the paper. I do not believe this is an illigitimate procedure since the filler is the same, the parameters the same, the material the same, and the material specs do not require that you establish dual cert if a material is capable of it, they only allow you to do so if you want to.
In fact, I might take the argument one step further. Your MTR says you have 316L. Write your PQR up for 316L and the tensiles are good. Its thinking outside the box a bit but I do not see anything ethically wrong with it, because the whole dilemma is based upon a liberal acceptance of the dual certification idea.
Taking the philosophy of having to comply with the higher of the two is a conservative approach but I'm not sure its required.
I probably could have stated this more concisely, but I'm confident you'll get my point.