When this mistress noticed that her supervisor was unfair but he was also attracted to her, she knew that she had the means to do something about it. That is why she used her findom fetish to deal with him. She turned him into a pay slave and she had fun draining him financially. It was satisfying to watch him pay her for all his mistakes at the workplace. And he never even knew what was going on.
When mistress Deviant felt that she needed to dominate this guy and make him change his wayward behavior, she had to first hypnotize him in order to understand why he did what he did. And it was after she had gotten the answers she wanted that she knew how to tackle the issue and not only make him change, but also find a lasting solution. And she managed to do it.
This mistress did not want her human atms to be in debt and when she realized that one of them was, she knew he was not good at managing his money and that was going to affect her as well so she had to punish him and she did. She was not lenient with him as she knew she had to teach him money management so that she was assured of making money from him.