I wonder whether the efficiency trade-off translates into selling used equipment from their own mine. The second hand equipment they gave me in replacement of my faulty boards was definitely from their mine, but I wonder if they are selling second hand machines as new.
How long until you reach your ROI do you think? And how long have you been running your T9's?
Any machines I have purchased from bitmain used were clearly communicated to me prior to purchase. I have never received used hardware that was sold new. I do apologize for not being able to answer but I do not disclose financial information on this forum. I have multiple batches so there is no specific answer for your final question.