I'm looking for some definitive proof one way or another that would prevent hard shot or CCW form being used in lieu of regular hardness media.

I'm not talking about what it says on the print or specification to use. I want to know if there is hard evidence that would convince me that hard shot should not be used on soft material i.e. aluminum. I am trying to convince an OEM that AWCH (AMS-2431/8) is the way to go across the board. I already know for a fact that AWCR will increase in hardness overtime with use. So I don't see why AWCH can not be used.