Over penetration in a handgun round is largely a my much as hydrostatic shock and knockdown power as evidenced by the report itself. If the report is to be believed at all then the statement about hollow point expansion reliability is to be considered. Therefore if the percentage of expansion is let's say 50% then the 50% that fails to expand very much acts in the same manner as ball. Not identically because of deformation. And the report fairly clearly states that penetration of at least 12 inches is critical to reach critical structures which is where the real incapacitating effects come from. And the only true incapacitating effects for a "one shot stop" comes from disabling the CNS or brain. Further that a significant amount of kinetic energy is dissipated in the body itself and that the elasticity of the skin at the rear of the entrance hole is sufficient to prevent over penetration.
I believe the report itself states that there is no conclusive evidence or study of actual shooting incidents that would demonstrate anything to the contrary or that would support the common beliefs in JHP and expanding bullets. Otherwise the military would likely be using such ammunition, would they not?