Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/18b/fapap/Use_cURL.html REST API = REpresentational State Transfer (REST) Application Programing Interface (API)

Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19a/fapfm/implementing-project-financial-management-applications.html#FAPFM969761 Topic - Entering Planning Resource Breakdown Structure Details Click Navigator > Setup and Maintenance, and search for the Manage Planning and Billing Resource Breakdown Structures task.
Click the Manage Planning and Billing Resource Breakdown Structures link.
Use the Manage Planning and Billing Resource Breakdown Structures page to create new planning resource breakdown structures and to review existing planning and billing resource breakdown structures.
Click the Create icon in the Planning Resource Breakdown Structures section.
Use the Create Planning Resource Breakdown Structure: Basic Information page to provide basic resource breakdown structure information including the name, active dates, and project unit.
Enter a planning resource breakdown structure name and select a date from which the resource breakdown structure is available for use.
Optionally, provide a description and a date to which the planning resource breakdown structure is available for use.
Select a project unit. Only projects created for the selected project unit can use this planning resource breakdown structure.
If you want to allow project managers to add planning resources at the project level, then select the Allow resource changes at project level check box.
Tip: Changes at the project level don,t move back to the parent planning resource breakdown structure. Deselect this option to ensure all project using the planning resource breakdown structure use the same resources.
Optionally, select a Job Set as a source of jobs for creating planning resources on your planning resource breakdown structure.
Click Save.

Ref:https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19a/faopm/subjectareas.html#Projects__Cross_Subject_Area_Analysis__Real_Time_SA_20 Analyze real-time information on project performance, including budgets, forecasts, costs, commitments, revenue, and invoices.
This subject area analysis allows cross subject area analysis between Funding, Invoices, Revenue, Budget, forecasts, Costs areas.

Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19b/oapjb/manage-project-contract-revenue.html#OAPJB164173 Associated Project Percent Spent Example The following formula calculates the percent spent revenue for the associated project.
((Sum of ITD Actual Cost for every subtask that is part of the associated task / Sum of Total Budgeted cost for every task that is part of associated task) x Associated Project Funded Amount) - Sum of Existing Invoice Event Amounts for the Associated Project ((60/300) x 750) - 80 = 70 ((Actual Cost / Budgeted Cost) x Budgeted Revenue) - Sum of Revenue Event Amount