Why are these 2 code blocks not the same?

[mmscg]

These 2 code blocks should function identically, I would think.

I marked in bold the only thing I changed (2 places).

This code functions properly:

#define MAX_SECTORS_PER_READ    27
#define RAW_SECTOR_SIZE     2352

ULONG  sectorsPerRead;
ULONG  bytesPerRead;

sectorsPerRead = MAX_SECTORS_PER_READ;
bytesPerRead = sectorsPerRead * RAW_SECTOR_SIZE;

fSuccess = DeviceIoControl(pextr->hCDROM,
                           IOCTL_CDROM_RAW_READ,   
                           &info, 
                           sizeof(RAW_READ_INFO),  
                           smpl,
                           sectorsPerRead * RAW_SECTOR_SIZE,      
                           &bytesRead,             
                           0);                    

if(bytesRead != sectorsPerRead * RAW_SECTOR_SIZE) __leave;

This one fails:

#define SECTORS_PER_READ    27
#define RAW_SECTOR_SIZE     2352

ULONG  sectorsPerRead;
ULONG  bytesPerRead;

sectorsPerRead = MAX_SECTORS_PER_READ;
bytesPerRead = sectorsPerRead * RAW_SECTOR_SIZE;
                  
fSuccess = DeviceIoControl(pextr->hCDROM,         
                           IOCTL_CDROM_RAW_READ,  
                           &info,                  
                           sizeof(RAW_READ_INFO), 
                           smpl,                   
                           bytesPerRead,           
                           &bytesRead,             
                           0);                   

if(bytesRead != bytesPerRead) __leave;

These makes no sense to me, as I see them as identical.

Am I missing something here?