The only way to figure out where the prevailing fees will settle is to test the quotes to see which get accepted vs rejected. Bear in mind that some appraisers have already said they won't participate in those assignments. My PFA guess is that the percentage will vary by locale so -10% in one market may end up being -20% in other markets. There's no way to know what will work in your area without testing for the sweet spot.
Res lender reports ordered trhough an AMC gets far less as a fee accepted, and by now you know the reasons. This is not a free market, where the customer gets to choose the appraisal, for one thing.
Other professions, including the rest of the appraisal profession, are free markets where a professional has access to thousands or hundreds of thousands of potential customers. Just for a start - the conversation can go on forever
As an example, my computer tech guy 6 years ago charged $75 an hour (going rate at the time ); now he charges $150 for the first hour and $125 each hour after that. Of course, his customers are allowed to select him . There are no prohibitions about who is allowed to engage him.
My hairdresser (colorist ) - four years ago the fee was $60. Now it is $90. She books 4 people an hour at 15-minute intervals. Even if she splits her fees with the salon, or has some dead time, she makes more per hour than I do. Again, she is free market and anyone can engage her .
I would tell any young person or even mid-career person to run, not walk, run away from res appraisals if their customer base is mortgate lending. They can make more as a hairstylist. As a dog groomer. As a TSA agent. As a corrections officer. As a health care provider. As a computer tech person. As a teacher. Or they make the same lousy money as a real estate license appraiser but with a low-stress or rewarding job or a job that fulfills a mission. The military is a great option if one is the right age.