It is possible to set a default time off duration for your employees that is different from the default value set in the time off settings.
To do this, first go to your employee's profile via the "HR" -> "Employees" tab.
Once in your employee's profile;
Select the "Settings" tab
Activate the parameter "Override the organisation's default time off duration"
Enter the desired value
Click on "Save"
This value will then be automatically used when you accept a time off request or create a manual time off. Note that you can still modify it if necessary.