OK. I was presuming how MQA data is embedded in stereo files. Still, if that's how its done for stereo, it is likely the same is done for multichannel and, to be honest, it is likely that only Bob Stuart knows for sure. But, since multichannel PCM is sorted out in pairs without MQA, having MQA data should not make any difference. I handled those files as I have all multichannel files with many DACs.
Added in edit: I found a metadata tag on one of the 4.0 tracks: "6ch MQA as pairs L R 0 0 Ls Rs." I also found there were channel test tracks provided.