[Izverg04]

Personally, I don't know because I don't play no limit. First of all, this could be a fluctuation. I estimate about 1.5 sigma between your numbers being equal with your samples.

I suppose that in no-limit variance is driven by how often you go all-in, not how often you voluntarily enter the pot. There is some positive correlation between the two for sure, and some negative correlation between the number of players and how often you go all-in. With more players, you find more often another strong hand to go all-in against your strong hand preflop. The same effect is not as important in limit because the pot never gets as big even with 2 strong hands against each other.