In my previous shop, I used to qualify all our WPS' with impacts (well, only those materials where many codes typically require impacts), and then used them freely on materials which did not require impacts. This way I had all my bases covered.
I had to explain this to an auditor once or twice because he was trying to apply my impact notations while I was using the WPS for non-impact work. It would probably be "cleaner" for me to have simply developed a second WPS but that's an after-thought.
Thanks jon. I am of the same opinion. Now I'm quite confident I am doing it right. I'll be on a trip to visit one of our "problematic" project. Regards!