There's your problem. The UA MP numbers are three letters + five numbers. Is your third letter a capital O and you thought it was a zero?
2 + 6 here!
From what I've seen in my company and my family, those who obtained numbers before the merger got 2+6. Those right after the merger got 3+5. However, earlier this year, I signed my young daughters up and they both got 2+6 as well. So I don't think there is actually any rhyme or reason to it.