How is Task Duration Calculated in Oracle Fusion Project Execution Management (Project Plan)?

Hi Experts,

I am exploring the Project Execution Management functionality in Oracle Fusion and have a question regarding task duration calculation in the Manage Project Plan page.

I created a test project with the following task:

• Start Date: 01-Jan-2026
• Finish Date: 01-Feb-2027

Oracle calculates the task duration as 283 Days.

However, the elapsed calendar days between these two dates are 396 days. Even after excluding weekends, I'm trying to understand the exact logic Oracle uses to derive the duration.

As part of my testing, I have also:

• Created a new Project Workday Pattern with End Day = 7 (instead of the default 5-day work week).