CRC problem

I have used this C code posted by others in the forum. But i found that i can only do CRC for 7 bytes. Is it the problem of only 16 elements in the feedback array? or why?

/****************************************************************************
 *
 *     NAME: Crc8()
 *  PURPOSE: Generate 8-bit CRC.
 *
 *  SYNOPSIS:   unsigned char Crc8(unsigned char b, unsigned char initCrc);
 *
 *  INTERFACE PARAMETERS:
 *
 *      Name                 FG-IO  Description
 *      -------------------  -----  -----------------------------------------
 *      b                    F  I   Data byte to CRC (MSBit first).
 *      initCrc              F  I   Initial CRC or CRC accumulator for
 *                                  continuation.
 *      <return value>           O  CRC.
 *
 *  DESCRIPTION:
 *
 *      The function returns the 8-bit CRC after including "b" with the
 *      initial CRC "initCRC".
 *
 ****************************************************************************/

static const UCHAR code feedback[16] =
    {
        0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
        0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D
    };

UCHAR CRC8(UCHAR b, UCHAR CRC)
{
    CRC = (CRC << 4) ^ feedback[((CRC) ^ b) >> 4];
    CRC = (CRC << 4) ^ feedback[((CRC >> 4) ^ b) & 0x0F];
    return (CRC);
}