If a package job is created due to a new job or if it is open due to being vacated, either way, package classification gets first crack at it. Even a package driver that currently holds a bid can bid on this new job and make a change. Then his old bid would be open and put up for bid.
According to the OP, no package driver bid on it. Now he is bidding against other full time employees. The highest senior full time employee will win the bid. In this case, he was the only FT employee to bid. So he wins it. If he did not bid, and no other FT employees bid on it, it then gets opened to part time employees. Unless they fill it from the street before opening to the building or part timers. They can do this as long as they are meeting their ratio. In the Central, it is 6 for 1.