Why did aero do this? - Aero Precision M5E1 Handguard Barrel Nut

In order to use one of their "Enhanced" Handguards, unless you have the proper receiver, you have to use this barrel nut. It only has 4 channels for the gas tube to go through. To ensure proper timing they included 5 spacing shims. Problem is even with all 5 shims the channel never lines up. So you can either return every you bought and change manufacturers, or buy yet another pack of shims from them for $6. Why would they sell such a poorly designed system. At the very least include enough shims to properly time it. I recommend going somewhere else. Aero usually makes good stuff. But this is lousy.