Starcom, the bonus card punches are never allowed to be used on any of the other offers. It is not a glitch. The reason is understandable. THere would come a point that you could manipulate the credits so much with the specials they have that you'd end up just getting games for free nearly all the time. With their prices so low already and relying on quantity buying, they and the developers would never make any money to develop and produce more games.
Sorry you missed out on the sale because of this.