The guys are flying with the DJI WKM Mixer X8 mixer which by default does not reduce or increase the rpm for the top or bottom props. I think though that they are flying slightly modified mixer in order to have one herkules board taking care of either the upper or lower props which would give them extra redundancy if one herk board failes. You would remain with a quad. Probably with the KW 10 they are flying 15 or 16 xoars probably 16 xoars
Boris
Thank you. Interesting, It would be amazing if they could confirm this.