OK, here's an example breakdown for the dpms 64-bit AHCI Intel drivers.
Unique HWIDs are in GREEN and duplicated HWIDs are in RED.
x64\All\M\Intel\1\iaAHCI.inf DriverVer=11/06/2010,10.1.0.1008
PCI\VEN_8086&DEV_2681&CC_0106
PCI\VEN_8086&DEV_27C1&CC_0106
PCI\VEN_8086&DEV_27C5&CC_0106
PCI\VEN_8086&DEV_2821&CC_0106
PCI\VEN_8086&DEV_2829&CC_0106
PCI\VEN_8086&DEV_2922&CC_0106
PCI\VEN_8086&DEV_2929&CC_0106
PCI\VEN_8086&DEV_3A02&CC_0106
PCI\VEN_8086&DEV_3A22&CC_0106
PCI\VEN_8086&DEV_3B29&CC_0106
PCI\VEN_8086&DEV_3B2F&CC_0106
PCI\VEN_8086&DEV_3B22&CC_0106
PCI\VEN_8086&DEV_1C02&CC_0106
PCI\VEN_8086&DEV_1C03&CC_0106
x64\All\M\Intel\2\iaAHCI.inf DriverVer=10/17/2011,10.8.0.1003
PCI\VEN_8086&DEV_27C1&CC_0106
PCI\VEN_8086&DEV_27C5&CC_0106
PCI\VEN_8086&DEV_2922&CC_0106
PCI\VEN_8086&DEV_2929&CC_0106
PCI\VEN_8086&DEV_3A02&CC_0106
PCI\VEN_8086&DEV_3A22&CC_0106
PCI\VEN_8086&DEV_3B29&CC_0106
PCI\VEN_8086&DEV_3B2F&CC_0106
PCI\VEN_8086&DEV_3B22&CC_0106
PCI\VEN_8086&DEV_1C02&CC_0106
PCI\VEN_8086&DEV_1C03&CC_0106
x64\All\M\Intel\3\iaAHCI.inf DriverVer=11/29/2011,11.0.0.1032
PCI\VEN_8086&DEV_27C1&CC_0106
PCI\VEN_8086&DEV_27C5&CC_0106
PCI\VEN_8086&DEV_2929&CC_0106
PCI\VEN_8086&DEV_3A02&CC_0106
PCI\VEN_8086&DEV_3A22&CC_0106
PCI\VEN_8086&DEV_3B29&CC_0106
PCI\VEN_8086&DEV_3B2F&CC_0106
PCI\VEN_8086&DEV_3B22&CC_0106
PCI\VEN_8086&DEV_1C02&CC_0106
PCI\VEN_8086&DEV_1C03&CC_0106
PCI\VEN_8086&DEV_1E02&CC_0106
PCI\VEN_8086&DEV_1E03&CC_0106
Now you would think that the logical action would be to remove folder \2 because it's duplicated between folders \1 & \3, BUT...not all the HWIDs in folder \2 are duplicated in the newer folder \3.
My motherboard has PCI\VEN_8086&DEV_2922&CC_0106 which isn't supported by the newer folder \3. So my best match is folder \2. I wouldn't want to be stuck with the older driver if I didn't need to be and I'm not the only one that feels that way.
The 32-bit dpms is similar.
So if you can prove that one folder ON IT'S OWN fails, then we can remove it from the pack. One of the great things about the DriverPacks is that they are modular and you can add/delete/modify each one to suit your needs.
Looking at the IaStor drivers it's probably perfectly safe to remove the v10.8.0.1003 iastor.inf (and sundry) because it's a 100% duplicate with v11.0.0.1032
I'm sure that more testing is in order though.
*Edit
Oh, and editing the .inf will break driver signing and the Windows setup will use ANY other matching driver as long as it's signed. That's one of the quirks with driver signing is that setup will always default to a signed driver over any other driver.
*Edit 2
I'll try to confirm your bug on my system using your methods.