I am not a big statistics guy. But I will say that I believe all handguns are underpowered and to win consistently you should be dedicated to extreme close range accuracy under stress. Shot placement, shot placement, shot placement.
And considering that, you are making the same mistakes accuracy wise at 3 feet, that you are making at 30 yards. It just isn't as noticable. So if you can stack rounds at 3 feet, you will shoot well at 30 yards. If you can't stack rounds at 3 feet, if you are even a little sloppy because you can get away with it up close, you will probably be sloppy aiming in a close range self-defense shooting.
In simple terms I'm saying that your low and left shot in the kill zone at 5 yards, will probably be a low and left shot to the right arm in a fight, or a complete miss. So dedicated yourself to perfect shooting at all times.
In simpler terms, just because you hit a lung or heart on a paper target and got it in the kill zone does not mean you hit where you were aiming. Center mass should be dead center of where you are aiming.
I have shot many qualifications scoring 100 percent and was very unhappy with my shooting.
I Image it was either High Accuracy and Low Precision or Low Accuracy and High Precision