0.01% THD = -80 dB
0.06% THD = -65 dB
...and plug-ins usually add more harmonics than HW versions cause like that people can easier hear that added saturation, so everybody can conclude how 'analog' those plug-ins sound. It just shows big popularity of saturation and 'analog' that plug-in designers follow these days. Softube are usually honest without exaggerating things...or I just like to think so.