The codes have been deleted from the tickets for a couple reasons.
First, the codes were started before computer validation existed. Now that tickets are validated by computer, the codes are not necessary.
Second, we found that many players were misinterpreting the codes. They were never in place for players to determine whether they had winning tickets, but players used them for that purpose. This often resulted in players either thinking they had a prize greater than what they did, or thinking they had a non-winning ticket when in fact they had a winning ticket.