The response I received is as follows "Your Appraiser is and was aware that sales 1 and 2 (the two units in my condo that were used for the appraisal) have lower level finish It was included in the GLA  due to the fact that these units were all finished at the time of conversion (the condo was created and basement finished in 2005 when a developer bought the former mansion and split it up into units) with similar material and quality.

I can't take the same logic I use to design a small 1200 sf SFR and apply it the a mansion that is 12,000 sf. 

It's easy for out of state investors to spin their wheels looking at properties out here when you've got lakeside mansions just a few streets away from serious blight. 

I mean who would want to rent a mansion for $20,000/month?

Mega malls, professional sports stadiums, expansive shopping centers, ten+ bedroom mansions, etc.Maybe this has happened many times in past sellers' markets but for those of us who haven't been in the industry too long, is this normal?

Was he living in a mansion?

The guy was an honest guy, its just that his business was growing exponentially and from the first day that I started working with him, he always talked about getting his mansion. 

The SF houses range from 20$ per square foot for a run down overgrown foreclosure up to 50$ per square foot for a mid century mansion in decent shape.

But if you move from a basic, 1000 sq.ft. house to a 5000 mini-mansion, the improvement is much less. 

By the time your 30 you will want to flip large apartment units and mansions!