Build the supporting documents. These should develop your arguments and detail how you reached your conclusions. Relatively few people may read these documents thoroughly, but those who do can be important to you. Base them on your company's accounting rules. Have your financial team member verify them.
Financial analysts focus on details.
Be sure you satisfy them. Project plan . While a basic cost justification may not require a project plan, it will be needed if it involves funding by other departments or commitment to the process. You need to develop a project plan in order to appreciate the relationships between tasks, activities and resources. Ask other successful project leaders in your company to advise you about how much detail to present in your cost-justification proposal.