He was an anesthesiologist who worked in Maryland and Virginia.  "Soliman lived in a condominium in McLean, Virginia. His residence had a spare bedroom which he used exclusively as an office. Although he did not meet patients in the home office, Soliman spent two to three hours per day there on a variety of tasks such as contacting patients, surgeons, and hospitals by telephone; maintaining billing records and patient logs; preparing for treatments and presentations; satisfying continuing medical education requirements; and reading medical journals and books."

And still he lost at the Supreme Court, so Congress amended the law.  If someone has an area used exclusively for business, two or three hours a day, it's a home office.  If someone works from the kitchen table an hour a week, sending out bills, it's not.