Problem with #elif

Using Arduino Programming Questions
7

More strangeness:

WORKS:

#define PACK_STYLE 0

#if PACK_STYLE == 0
  const byte BARGRAPH_STANDBY = 1; // Safety on
  const byte BARGRAPH_IDLE = 2; // Ready to fire
  const byte BARGRAPH_FIRE = 3; // Black button
  const byte BARGRAPH_ALTFIRE = 4; // Red button
#endif

WORKS:

#define PACK_STYLE 1

#if PACK_STYLE == 1
  const byte BARGRAPH_STANDBY = 2; // Safety on
  const byte BARGRAPH_IDLE = 1; // Ready to fire
  const byte BARGRAPH_FIRE = 3; // Black button
  const byte BARGRAPH_ALTFIRE = 4; // Red button
#endif

DOESN'T WORK:

#define PACK_STYLE 1

#if PACK_STYLE == 0
  const byte BARGRAPH_STANDBY = 1; // Safety on
  const byte BARGRAPH_IDLE = 2; // Ready to fire
  const byte BARGRAPH_FIRE = 3; // Black button
  const byte BARGRAPH_ALTFIRE = 4; // Red button
#endif

#if PACK_STYLE == 1
  const byte BARGRAPH_STANDBY = 2; // Safety on
  const byte BARGRAPH_IDLE = 1; // Ready to fire
  const byte BARGRAPH_FIRE = 3; // Black button
  const byte BARGRAPH_ALTFIRE = 4; // Red button
#endif