My MIL was one who would have shown to be making money each year beyond what she was required to purchase. However, she didn't just purchase her required amount every month. Many months, she would purchase the monthly requirement for several in her down line to make sure she was getting her max commissions. So she was spending money that would not show up in those calculations, making it appear she was turning a small profit (somewhere in the "less than the $28k" group), when in reality she was spending it all back on DoTerra.
Even her upline seemed to have similar problems. The couple that she was under are allegedly making like $30k or more a month. But she learned of a time they were in Japan trying to get people going there and they found out that all of their credit cards had maxed out. I suspect they were doing the same things to ensure they kept a large income by buying tons of product under other peoples accounts, essentially maxing out all of their credit cards.