Why do Rennick's lines warm up as such high speeds?

I've always noticed that Rennicks lines and books really push hard on dynamic extremes. Their softs are extra soft and their louds are extra loud. But whenever I see his lines warm up it always appears to me that they play their packet at much faster tempos than other lines.

Are my ears deceiving me? Is there some reason Rennick's lines like to jump in with their legatos, double beats, rolls, flams, etc. at a higher tempo than other lines?