Why some financial plan types aren't available while generating forecast versions?

Some financial plan types aren't available to generate a project forecast version.

They aren't available to generate a project forecast version based on the following:

• If a forecast version that belongs to a primary cost or revenue forecast already exists for the project, then the financial plan types that are designated as primary cost or revenue forecasts aren't available for your forecast generation.
• If the project belongs to a project type, that isn't enabled for billing, then the financial plan types that can capture revenue planning amounts aren't available.
• If the financial plan type isn't assigned to the same reference data set that's assigned to the Project Definition reference data object of the project unit to which the project belongs, then the financial plan type isn't available.
• If the financial plan type isn't enabled for multiple transaction currencies, then you can't generate the forecast version from a source plan version where the Enable planning in multiple transaction currencies option is enabled.