http://www.bjs.gov/content/pub/pdf/htus8008.pdf

There are only 250-500 cases of justifiable homicide per year in the US from 1980-2008, in contract to 20,000-30,000 of total homicides in the US each year. These are not surveys, they are total numbers.
It is in direct contrast to the number you cited about home defense of 2.5M (I think it is 250,000, I looked at the original paper on your references) per year with 750,000 lives saved. You better check your numbers more carefully, I think there is something wrong in your numbers. These numbers you cited is way above any sources I read anywhere else.