You saw when creating a project that you could choose to make it statistical. You want to understand the impact of this decision in how you use the projects.
In case you need to have two or more analysis viewpoints for a controlling relevant posting, you will need to understand and utilize real and statistical postings.
For example, if you want to both follow-up on your travel expenses for a specific project and help the department managers see the costs for which they're responsible. You would use a double cost assignment to the project and the cost center. SAP S/4HANA is designed to only allow a single real posting per expense line item.
A cost center is always a real object. When a project is defined as real and an expense line item is posted to both a real project and a cost center, the project takes precedence and receives the actual posting. The cost center is updated with a statistical posting.
When a project is created with the project profile Statistical Project (instead of Overhead Project), postings to this project will always be posted as statistical. To post to this project, you would need to also specify a real object to be updated (a cost center is usually derived by the statistical project master record and posted as the real object).
When performing reporting, these postings will be shown with the attribute statistical for the statistical project. They'll be shown without this attribute (as real postings) on the responsible cost center.
Statistical projects can't be debited with overhead rates or credited using settlement.