I am not going clear back through the thread, but I was under the impression that their 28nm devices will be based on the Bitmine Coincraft chips. These guys appear to be assemblers, rather than a straight up engineering company.
If they are using Coincraft for their 28nm miners, they should just say so. It would eliminate much of the doubt (at least when bitmine confirms this).
But let me point out that AMT specs dont seem compatible with bitmine's specs. AMT is listing "300-600W" for their 1.2 TH rig. Thats 0.25-0.5W/GH at the wall. Bitmine is only claiming an efficiency of 0.6W/GH at the chip level for nominal performance targets and 1W/GH in turbo mode. They do say it can probably go down to 0.35W/GH (IIRC) but at unknown speeds, and that is still at the chip level. For 1.2TH, 300W at the wall seems impossible with bitmine chips and less than ~800W at nominal speeds, very unlikely. And why would you not use the turbo mode initially?