Curious, why the second cast?

#define LOBYTE(w)           ((unsigned char)(w))
//! High nibble of 16bit variable
#define HIBYTE(w)           ((unsigned char)(((unsigned short)(w) >> 8) & 0xFF))

/* INT is processor specific in length may vary in size */
typedef signed int          INT;
typedef signed char         INT8;
typedef signed short int    INT16;
typedef signed long int     INT32;

/* MPLAB C Compiler for PIC18 does not support 64-bit integers */
#if !defined(__18CXX)
__EXTENSION typedef signed long long    INT64;
#endif

/* UINT is processor specific in length may vary in size */
typedef unsigned int        UINT;
typedef unsigned char       UINT8;
typedef unsigned short int  UINT16;
/* 24-bit type only available on C18 */
#if defined(__18CXX)
typedef unsigned short long UINT24;
#endif
typedef unsigned long int   UINT32;     /* other name for 32-bit integer */
/* MPLAB C Compiler for PIC18 does not support 64-bit integers */

/*                FRAM SPI DRIVERS 2Mb FRAM
  * uint8_t Fram_READ(__uint24 FramAddr);
  * READ_address 0000 to FFFF, page 00 to 03     
  *
  * void Fram_WRITE(__uint24 FramAddr,uint8_t FramData); 
  *  WRITE  address 0000 to FFFF, page 00 to 03 ,WRITE DATA .   
  *
  * void Fram_WREN();
  *  SET WRITE ENABLE LATCH
  *
  * uint8_t Fram_RDSR();
  *
  * void Fram_WRSR();
  *
  *  * Name   description            Op-code
 * WREN Set Write Enable Latch   0000 0110 B
 * WRDI Reset Write Enable Latch 0000 0100 B
 * RDSR Read Status Register     0000 0101 B
 * WRSR Write Status Register    0000 0001 B
 * READ Read Memory Code         0000 0011 B
 * WRITE Write Memory Code       0000 0010 B
 * RFID Read Device ID           1001 1111 B
 * FSTRD Fast Read Memory Code   0000 1011 B
 * SLEEP Sleep Mode              1011 1001 B
 *
 */