Dear Bob,
you are not far from the right...nevertheless I can say that after 2 years of work experience in a biotechnology company, I am planning to do a PhD. This is because in the real world of work, it could be difficult to improve your expertise...in addition most of the company like to hire people who already know what to do. So in the real world there are not opportunity to learn new thing and go haed, where could you improve your knowledge?