IMHO the AMC likes to justify it's existence so there are *always* at least little changes. (IE comment on the style of the fireplace).
Actually, my revision rate with most AMCs is about 15% on refinances, and 30% on purchases. Not counting my mistakes. Once you start seeing a pattern of revision requests with a particular AMC/lender, just pre-address it in the report. I have found requests for another comp usually only come in 1) when my value is below SP, or 2) if something the underwriter thinks is important is not bracketed. I can usually tell what those might be, and try to address those too, explaining why it could not or was not bracketed--my market is largely rural so bracketing everything can be nearly impossible. Lucky to get 3 good sales sometimes.
Most of the revisions requests I do get are because my market is rural and the U/W in the big city doesn't understand that sometimes there just aren't any good comps for a certain amenity to be bracketed. Sometimes across-the-board just has to happen. Fannie's C/U is brutally stacked against rural appraisers, IMHO. My favorite was "appraiser to explain why 1 mile guideline had to be exceeded." Because subject is rural, not urban, and there are only 16 homes within a one mile radius of subject, and regrettably, the one home of those 16 that is similar to subject had the audacity to not sell in the last 12 months.
One lender demanded live, IN-SEASON comp pics. So if I visited a comp in March, and 2 months later used that sale again for a different report, they would need new pictures. Don't work for them anymore either. I don't inspect the subject twice, not gonna inspect the comps twice either.
Bottom line, you have the choice of who your clients are. I know finding new ones is hard, but being an independent appraiser is sometimes as much about being a good business person as being a good appraiser. Better to go hungry for a week finding better clients, than hating your job the rest of your life.
Of course (and nothing personal, I've never seen any of your reports) it could just be your reports do have issues that most reports would not have. Look at every revision request as an opportunity to become a better if not appraiser, than report writer at least. Tell the story they need to hear, but in the words they want to hear.