This is the problem, there is no universal body regulating PE licensing and all the states have their own rules and regulations. It is a tedious process trying to stay updated on which state require what registration and when you are licensed in multiple states, the process is quiet a headache!
I still do not understand the "benefit" of having to register with the Secretary of State, especially if an engineer do not hold an office in that state. As it stand, you may as well become incorporated in every state as most now require a COA and SOS registration.