The current explantory text for Process Control includes
"A Process Step can be as big or small as the designer of a particular Business Service chooses. From a design perspective, one Process Step can contain "sub-steps", each of which is conceptualized as a (smaller) Process Step in its own right. Each of those "sub-steps" may contain "sub-steps" within them and so on indefinitely. It is a decision for the process designer to what extent to subdivide steps. At some level it will be appropriate to consider a Process Step to be a discrete task (unit of work) without warranting further subdivision. At that level the Process Step is designed to process particular Process Inputs, according to a particular Process Method, to produce particular Process Outputs."
I suggest that this part is moved to the explanatory text for Process Step.
The entire explanatory text for Process Control would then be "A Process Design is the design time specification of a Process Step that is performed as part of a run-time Business Service. The flow between a Process Step and any sub steps is managed via Process Control."