You raise an important point, but the record shows that CMS was aware, and asked Mylan to stop doing this[1]. If your error is pointed out and you continue doing it, that's certainly fraud, no?

1. http://www.cnbc.com/2016/10/05/mylan-accused-of-bilking-taxp...

with the relevant paragraph:

> CMS "has, on multiple occasions, provided guidance to the industry and Mylan on the proper classification of drugs and has expressly told Mylan that the product is incorrectly classified," Slavitt wrote.