Like most IWs, it is the timing, not the code that determines the winner. Here's what the Rules say:
"WINNER SELECTION. One Prize Pack is available at a randomly selected time ("Winning Time") every quarter hour of each day of the Promotion Period, for a total of ninety-six (96) randomly selected times per Promotion Period day. The Winning Time of Game Play will determine whether a participant is a potential winner in the Game. The first person to play the Game at the Winning Time or after will win a prize, subject to verification. The Winning Times will be randomly seeded every fifteen (15) minutes throughout each day during the Promotion Period by a computer program. The odds of winning a Prize depend on whether a Game Play falls at the quarter-hourly Winning Time or is the first Game Play after the Winning Time for each quarter-hour of the Promotion Period. Limit six (6) Game Plays per day of the Promotion Period per person regardless of method of play. Limit one (1) prize per person."
Because of your question, I tested out reusing the code I used a few hours earlier and it counted as a play, and I got the usual losing message with one less play left. This was only once, so I don't know if you can just reuse the same code over and over. I've been getting a new batch every few days when I run out (I don't enter 6X/day).