(a) A state licensed or certified real estate appraiser may not accept a fee for an appraisal assignment that is contingent upon the appraiser reporting a predetermined estimate, analysis or opinion or is contingent upon the opinion, conclusion or valuation reached or upon the consequences resulting from the appraisal assignment.
(b) A state licensed or certified real estate appraiser who enters into an agreement to perform specialized services may be paid a fixed fee or a fee that is contingent on the results achieved by the specialized services.