The general rule is, yes, the package is only available for the first show.
However, usually the second show wont fill up as quickly so you dont really need the package for the second.
We saw the second show during Christmas week, 2003(without the package). It was fairly early for a second show(I want to say maybe 8:30). We arrived 20 minutes early and got 4th row seats in the second section in from the left. Throughout the show the sections on either end(the far right and far left) remained empty.
Good luck!