Is there a way we can add DFF in the Manage Forecast Version?

Summary:

I only see 2 options, the Plan Lines and Planning Options.

But it is not advisable in Plan Lines, because we can't add manually each lines(what if more lines).
Same with in Planning Options.

Is there a way we can add DFF in the Manage Forecast Version? or Custom Fields in Manage Project Financial Plan
The Business wants to add EVM(Earned Value Management) field temporary manual inputted to track the Project Performance.

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