I think it may be that your license is for 500 Tons or less. I think because the OSV limitation is only a domestic endorsement that it doesn’t count towards STCW for 500 Gross Tons or more. That’s just speculation but that’s the only difference I can see between what I had and what you had. My school cert reads the same as what was posted above. I had a 1600 NC and a Less than 3000 NC international. Just a thought.