This isn't quite right. I'm a CPS attorney and served many years in drug court. The upside to a hair follicle test isn't so much related to levels. The two main benefits of the hair follicle test are 1) it is 99% accurate (the instant read ones they use in the field are way less accurate) and 2) the hair follicle test can detect use within the prior 90 days.
This story enrages me. It is so damaging to so many people. She had to randomly generate positives because if she processed thousands of tests with zero positives, it would be a major red flag. Speaking from personal experience, that lab confirmed positive is a silver bullet in court. People lie about their drug use all the time. Field tests are so unreliable that protests of innocence based on the field test can at least be plausible. A lab confirmed positive? Suddenly that person is treated as a liar and their credibility is undermined. It completely changes the tenor of a proceeding. The hair follicle test with mass spectrometry is 99% accurate. Falsifying that is devastating to the wronged sample giver, to the children, to the judicial and child protective systems, to public trust, and to future cases.
I'd have given her the full 99 years.