I'm am looking at 2 different integrated amps for future Sierra 2 speakers but there is something I don't understand about the 2 I am looking at related to THD?

I am looking at the following 2 integrated amps:

1. Peachtree Audio Nova 150
2. NAD C 388

These are both almost identical in price and specs except for THD rating: the Nova 150 says less than 1% THD the NAD C 388 says less than .009 THD that's like 100 times difference mathematically? Can somebody explain to me what is going on in this case with the THD spec - does the Nova 150 really have 100 times more harmonic distortion than the NAD?

Thanks