Someone clock me if I'm wrong, but I think this is true until you change your username AGAIN. So Josh could become "BjörkRulesKatyDrools," but Josh would be reserved for him in case he wanted to go back. Then if he changed his username 90 days later to "Joni4Life," Josh would be freed up finally and BRKD would be reserved for him instead.
I forget and may be completely wrong, but certain exceptions can be made especially since it seems that account was banned due to a duplicate IP and never had any posts. So try a HR, the worst that can happen is a no.