The original idea, I now understand, is to have an API endpoint for the action of answering supervisor questions. That seems reasonable since, I believe, all other supervisor actions have an associated API endpoint.
My idea is a separate one: to allow both supervisors and HQ to change answers to questions. The rationale is to take account of a common pattern in surveys: a “supervisor” (i.e., Supervisor/HQ) receives an interview from the field, reviews it, has questions, calls the interviewer, discusses the issue, and agrees with the interviewer on changes to make. With other systems, this is possible. CSPro allows for this “secondary editing”. Working with raw data, one can make these changes in a script. With Survey Solutions, this process involves the “supervisor” rejecting the interview to the interviewer, having the interviewer make the edit and resend the interview, and asking the “supervisor” to review the interview again and approve/reject it. This adds a transaction to the process.