What does the "Zero Amount Revenue Flag" do in PA Event Details Window
In Oracle R12.10 Projects Billing Event Details Window there is a flag "Zero Amount Revenue Flag". It is unavailable due to a FRM-40200 (Field is protected against update) error.
What does this flag do and when is it available (what setup is needed / what events trigger it's availability)?
I haven't found any reference to it in Oracle documentation.
Many thanks to anyone who can provide some information.