We should update the Progress Note (V3) document template to include the Mental Status section as optional. For our behavioral health business, mental status is an important part of patient progress during ongoing treatment. For example, when a patient has been diagnosed with depression, our practitioners might periodically go through the PHQ-9 depression screening questionnaire to assess how the patient is progressing toward a goal. The HL7 example for PHQ-9 specifically recommends putting it in the Mental Status section. Or for another example see this presentation by the Los Angeles County Department of Mental Health on use of progress notes for mental health.

I understand that Progress Note (V3) is an open template and thus it is already valid to include the Mental Status section (or any other section). But this is a common enough use case that I think it's worth explicitly listing Mental Status as one of the contained sections. That way document recipients won't be surprised when they receive it.