I'm not sure how you can make these claims. To fully test your theory you would need identical rigs, one mining nicehash, the other nplusminer during the same period.
Yes, to FULLY TEST this I would need to go through a lot more trouble and buy another 6x 1080 rig, but seeing as none of you people are paying me to do any of this you'll just have to settle with me first doing a concurrent comparison between NiceHash and Zpool/NPlusMiner using my two rigs that are identical - each with a single GTX 1080 - and then use that as a baseline to establish relative profitability scaling when I run NPlusMiner on my 6x rig. So I will then be comparing a single GTX 1080 running NiceHash vs. 6x 1060 running NPlusMiner which I freely admit is not the most scientific way of doing a comparison, but it is "close enough for government work" as the old cliche goes.