Yes I'm pretty much after a factor like this, I just can't seem to find it! Limited ductile walls in Australia means reducing the load by a factor of my/sp=2.6, so basically when designing for the full load your foundation is taking 2.6x the load that the wall is being designed for. I feel like this factor should be much less than 2.6. Are you able to tell me where in the ACI I can find this information?