"Quantization"/Tempo Question

[connerton4]

Hi all,

I'm a big fan of Beatles Rock Band. I just started getting into the drums more seriously. I'm a DJ so I'm pretty familiar with the accuracy of quantized/loop-based/sequenced rhythm, and at this point I'm guessing that the tracks aren't, for a lack of a better word, "quantized" in Rock Band games. It seems like I need to adjust my tempo sometimes according to Ringo's fluctuations. Is this correct or did they actually use some sort of a high-end time compression plug-in to make the tempos perfect?