Sooo, when you get the order to do a earth bermed home, converted missile silo, underground monolithic geodesic dome, custom cave dwelling or on the opposite site a land locked converted paddle boat that could be re floated or something like a house boat on Lake Washington in Seattle etc. etc. My guess is you would turn them down because if I'm correct none of them meet ANSI guidelines and since you perceive ANSI as the law and not the guidelines that do apply to most but not ALL homes for determining living area (and therefore value) they all must be worth ZERO.
You probably try and stick with the safe little boxes that conform to all the rules in the book with those little adjustments for features and amenities since it does make it easier, you don't have to be creative, you really don't have tothink very hard or read for 2 weeks to catch up monolithic or composite materials trends and issues, it keeps you very safe.
Then again maybe you have done that.
When I did my first 80,000 dollar adjustment for a finished basement or that 50,000 for landscaping (the guy i worked for at the time routinely does over a million dollar adjustments just for landscaping) it was tough, but It does get easier as time goes by.
I like doing the easy 960 sft 3 bed 1 bath ranch just as much as everyone else. BUT the trend is that AVMs are more and more taking care of that for us. So whats left? The ones that don't fall in the "book", the goofy container homes, the mud brick homes, the geodesic domes, the 200 year old mansions, converted fire houses.
To be viable in the future of this business you're going to have to specialize in an area of styles and divergent cases that are on the edge of the "book" since those properties cannot be defined by a computer model, at least not yet.
So, you ask how we came up with the rule of design vs afterthought all by our lonesomes - 3 very good appraisers sat in a room for an hour scratching our butts looking at the pictures, starting and stopping on fruitless ideas, saying "I dunno" alot and "We should have charged more for this POS" until finally our God of an MAI walks in with 35 years experience and says "Do a slab up and correct for everything above the concrete, geeze why do I put of with you guys, you're useless" (there was a little more to it than that but you get the point)and then leaves. We in turn say yep, write up the why and how we did it that way and put it in the report. The next time we said "remember that one the boss called us a bunch of wannabees over?"
Also with heavy military training and a lot of nuclear weapons handling I learned early on the difference between a guideline, a policy, a rule and a law. And - can, should and must.