I have had three ARC Reference 160 stereo amps and two of the same model monoblocks. The monos produced at least two years before the stereo versions and the stereo versions produced over about a year. They all sounded exactly the same… first when unbroken in, and then when broken in. I have been very impressed how exactly the same they all sounded. The monos had a lower noise floor and a wider deeper soundstage than the stereo, but the sonic character was exactly the same.
So, I’m just guessing it is something unlikely to be of any importance. In theory it sounds good though.