I think (hope) that this recent FAQ from the FHA (which can pertain to any type of assignment) clarifies one thing for appraisers: if you do not like the fees and/or other terms being offered you for an assignment by an AMC (or, for that matter, a lender or any other party), REFUSE THE ASSIGNMENT if you cannot negotiate a higher fee or modify other terms!
This is purely a “business decision,” as noted in the FAQ, and appraisers are still responsible for producing a credible, USPAP-compliant report, no matter these contractual terms if the appraiser accepts the assignment.
[That is exactly what I did with a recent assignment from Norman Hubbard Associates, who wanted me to do an FHA 1004 for $260. I told them that I was not going to work that hard for so little money. They were very unhappy with me. :-( - Michael Tabor]