You have to realize the HUGE difference between a shot you can make, and a shot you can't miss.
I don't have any shots I can't miss, particularly in any kind of a pressure situation where I know a miss will cost me.
Of course, I don't mean literally CAN'T miss, but let's make up an arbitrary threshold of 97%. How many shots are there that you make more than 97% of the time you encounter them? For me, it's barely any. For pros, it's most shots. The difference between me and a player who can spot me the 7 and rob me blind, is nothing but a greater variety of 97% shots. I have good enough CB control to get through a lot of racks of 9-ball facing nothing but shots that would be 97% for a decent short-stop. But for me, they're maybe only 82% shots, and I don't get out.
Recognizing that shots you think you've mastered are still often only 80% shots, is important. 80% is not good enough to run out. You should only really be running 4 balls, if 80% is the best you can do. You need that number in the high 90's before you can start really running racks the way excellent players are supposed to, even if you have amazingly great CB control.
Practice those shots that are high-percentage, but not that high. Make them into REALLY high percentage shots. Those are the kind you need.
-Andrew