The present mechanic is to signal SAFE, and await an appeal (if there is one). The runner is considered safe when his body passes over the bag. Again, it is up to the defense to recognize that the runner missed the bag and to react accordingly. This goes for all codes
AFAIK.
BG, I dont see how your method can work in real life. Runner steps over the bag, then 10 steps later the ball arrives at the mitt and you call OUT? Then I guess you are shouting "he missed the bag!" to the horde of offensive coaches who are having heart-attacks on the spot? You cant call OUT-he missed the bag at the time, because the ball hasnt arrived yet....
I know you said 'banger' for the OUT call, but if there's no one accepted mechanic, then we dont know how close the play has to be to call it one way or the other. Doesnt work. The runner either missed the bag before the throw, or he didnt.