That depends.
For part of the project, the company will have to implement the audit results and/or strategies on its own. In this case, the final result will depend on the quality of the organization and implementation of the project to the end. As it was originally conceived and agreed at the beginning of the project.
For full project is launched (3 stages), the company pays the main (about 85%) part of the project cost upon its successful completion only.
P.S. I almost forgot - at least a dozen projects of different volumes and complexity have been successfully implemented. Comments on some of them can be found in the "Feedback"