Damn it, I forgot the best quote:
Kyoko’s work, Tomiya emphasises, is not prostitution, as no money is handed over. She earns a basic salary of £2,000-2,500 a month, plus bonuses when a case is successful, which they usually are.
She's not a prostitute, because she does not get paid by the people she sleeps with. She just gets paid for sleeping with them.
Huge difference.