The process model is a descriptive meta-model for process-oriented quality management and quality assurance approaches, not a prescription. An organization uses it in one of three ways: to describe one quality approach (choose it, find which processes it covers, describe it with the description categories); to compare several (the same steps for each, then a metric and an analysis); or to harmonize several into a consensus model. Good-practice profiles with specific guidelines, procedures or criteria can then be built on it, and the scheme can be extended.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.