yes and no and sometimes.
In my Kodiak .54x.54 yes definately a performance enhancer. In my Hawken, no tried it, no advantage was found, so I don't with this rifle. My .32 flintlock I am getting mixed results. The .32 has turned in 5 shot groups all touching, both with and without an extra wad, but then it has also turned in groups that are best called patterns with and without the wads. In this case powder compression seems to be critical, as does the amount of powder in the pan.