I think russ69 might have made the incorrect assumption that the OP was using both amps in stereo mode and bi-amping (28x4?). From what I can see, OP's talking about one stereo amp vs. two monoblocks. That said, the power difference still doesn't seem that great, but the channel separation and slightly better dynamic headroom would be the two advantages I can see with the monoblocks. That is not something that you might notice when comparing volume levels, but try some music with a lot of dynamic range and see if there's any noticeable difference.
Why would 2 schiit aegir amps sound the same as 1?
My setup is forte 3s, schiit freya+ preamp and 2 schiit aegir amps. They accidentally only sent 1 amp last week so I was able to trial my system for a week before my second amp came and I switched the aegir from stereo mode to two monoblocks. Yes my speakers are high sensitivity but I’m surprised I need to turn my volume dial to roughly the same spot on the dial. I was definitely expecting more going from a 20 watt stereo amp to two 80 watt amps. Overall I’m happy with the sound but maybe I just don’t need both amps?