Yes, he stopped using his nickname at that time. So? Last time I checked, one doesn't have to legally change one's name to start or stop using a nickname.
His School Record lists him as Barry Soetoro.
A registration document from a private school in Indonesia listed him as such when he was 6 or 7 years old. That doesn't mean he ever legally changed his to Barry Seoterro. Nor does it mean he ever went by Seoterro while at Occidental.
All it means is that he Seoterro as an alias when he was a child living in Indonesia.
He went to Indonesia and Pakistan before he started at Columbia,
As many US citizens did, on US passports.
and it is not a stretch (Since he never had a US Pasport until becoming a Senator for Illinois),
How do you know he never had a US passport until then? What's your source?
I just posted a long reply please read it.