The scope point is the part I'd turn into its own gate. Citation precision can pass on a sentence that cites the right study and still broadens it: sample to population, "was associated" to "is", descriptive finding to "clinicians should".
A citation-density filter rewards citing, so it can't see that drift. A densely cited report can still overstate.
What I'd want next to the four metrics: small paired fixtures where the source supports only the narrow claim, and the check fails on the broadened version even though the citation itself is correct. Scope-preserved and citation-supported are separate verdicts, and a blended report score shouldn't let one cover for the other.