Sigma Level for Service Processes

Hi All,

I am working in financial services company. The majority of our processes have 2 requirements: maximu allowed cycle time and correctness. I am struggling with calculating Sigma level for such situations. One of this measures is continuous (cycle time), another one discrete (coorectness). So, how do I treat them? Do I calculate Sigma levels separately using appropriate method for each data type and then what? Take smallest? Average? Or do I treat cycle time as a continuous measure and as an additional defect opportunity?

Thanks a lot!