I'm not sure I understand your issue, but let me take you through an example.
Document A uses
FormA. This form has a text field in it called "Subject" and in Document A this field contains the text "A test subject".
Your application also has "FormB" which is set to inherit values from the selected document. In our example, this form has a computed text field in it called "InheritedSubject", and this computes using the simple formula
"RE: " + Subject
When you highlight Document A in a view, and create a new document using FormB, any formula in that form will compute based on Document A. So, the "InheritedSubject" field will now contain the text "RE: A test subject".
Does that make sense?
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