The topic of accurate vs reasonable was covered when I took the USPAP Instructor Qualifications course. I didn't make any of it up.
The only place where "accurate" shows up in any of the SRs is in the reporting requirements:
Each _____ report must
(a) clearly and accurately set forth the appraisal (review) in a manner that will not be misleading.
(b) contain sufficient information to enable the intended user(s) of the appraisal (review) to understand the report properly, and
(c) clearly and accurately disclose all assumptions, extraordinary assumptions, hypothetical conditions, and limiting conditions used in the appraisal.
When is comes to the appraisers opinions and conclusions the operative term used in USPAP is "reasonable"and "credible", as in
When an
opinion of
reasonable exposure time has been developed..... .
The appraiser has a
reasonable basis for the extraordinary
assumption
The signing appraiser is required to have a
reasonable basis for
believing that those individuals performing that work are competent......
credible assignment results
credible appraisal
credible opinions and conclusions
credible analysis
etc - you get the point.
As I say, "accurate" is a term Fannie uses to characterize a value conclusion, and the rationale for why we shouldn't be that stoked on their usage of it is because it implies an unrealistic expectation of precision that we don't normally assert in our opinions and conclusions. And, as the course says, the first step of attaining credibility is to establish reasonable expectations.
As I say, none of this is original thinking on my part. I'm just regurgitating the materials I've been exposed to before.