Win32_DiskDrive not listing all devices

Hi,

I have 2 Windows Server 2008 R2.

Both of them have multipath installed. EMC Powerpath.

On Host A,

all the disks are listed in the Win32_DiskDrive class.

Eg:

DeviceID                      Model                                   SCSIBus            SCSITargetId        SCSILogicalUnit
\\.\PHYSICALDRIVE2     PowerDevice by Power...                       0                       1                      0
\\.\PHYSICALDRIVE9     PowerDevice by Power...                       0                       1                      0

On Host B,

Only unique Disks are listed in Win32_DiskDrive, even though the same disk is seen via multiple paths

DeviceID                      Model                                   SCSIBus            SCSITargetId        SCSILogicalUnit
\\.\PHYSICALDRIVE2     PowerDevice by Power...                       0                       1                      0

What makes the behavior of Win32_DiskDrive class change ?

Thanks for helping me out!