Level 15

"Drama" is right.  OIH is an emotional issue.  A man's home is not only his castle, it's his tax loophole.  Or at least he thinks of it that way.  "You'll have to pry this complicated Schedule C computation from my cold, dead hands."  

"Kicks" is right, too.  It's fun to watch the practitioners who still think there is a little man with a green eyeshade at IRS, attaching red flags to every return that indicates an OIH deduction.  

I admit, though, that the simplified method may result in substantially lower deductions in areas with higher costs to buy and maintain a home, than where I live.  And Congress has discouraged its use by moving more people to standard deduction, so their mortgage interest and property taxes are worthless on Schedule A.  (Nor does the SALT limit help.)  My ideal OIH client would rent a small 2-BR in a place like NYC and pay $3,000 a month for it.  15% of square footage times rent, utilities, insurance and how about holiday tips to the doorman?