Here's the skimpy on that Federal Flight Control wad. The FC wad that is in the 20 ga load is much softer than what Federal puts in their 12 ga load. Therefore, you will consistently see great results with the 20 ga Fed HW #7's out of ported chokes. My Indian Creek consistently broke the 150+ mark at 40 yards.
The FC wad in the 12 ga is very stiff and I think it does make a huge difference.