It sounds like the houseowner had a "rightious shoot" for the first shot, but there were a total of 4 and we may need to see what MD says about the last 3.
Adrenaline pumping and sudden lack of hearing from the first shot may have disoriented the shooter. The first shot hit the mark, but the recoil, or lack of training may have put 1 round above the guys head and the next 2 in the ceiling?
Not sure. To me, the validity of the 4 shots would be the succession. If there were 4 shots, 3 of which while the guy was half across the yard, obviously would not be valid. But if all 4 are found in the house in the same area (remeber, getting shot, the robber may have done some fancy diving and jumping combined with running and falling) and in succession, then I wouldn't see a problem with it.
/edit: Which brings us back to training....NEVER SHOOT JUST ONCE!!!!!!