I asked myself this question when I did my Six Sigma project. What if I landed up with 2 defects per million opportunities? I read some Six Sigma manuals and found that I could find my process at a higher level of Sigma. I got more encouraged when I knew that Airbus was operating at a 9 Sigma level. Design your processes efficiently. Who knows? You could one amongst the 9 Sigma or an even higher level.