Erowid's is the worst place to check the status of laws. I suggest FDA and DEA and then State by State laws. Erowid's tends to be outdated and under researched when it comes to law. However did you even read what was stated on the Eowids site? Here it is copied and pasted I guess I read the same thing you did what am I missing? The statement it that they can not verify state law shows they haven't got a clue.

U.S. FEDERAL LEGAL STATUS
LEGAL STATUS prescription only
SCHEDULE unscheduled

Tramadol (Ultram) is unscheduled by federal law in the United States, but is available by prescription only. This means that sales are regulated by the FDA, but possession is not illegal even without a prescription. Tramadol may be controlled under some state laws, but we have not been able to verify that

Take care. Billylll