so much for the guess that Bitmain only sold 2500 to each market.
http://miningpoolstats.stream/bytomlooks more like 5000 to each market (there are already 11225 machines online and rising), plus they might be running a third batch. this explains why earnings was already down to 40-42 yesterday.
It wasn't a guess. Most Bitmains customer service representatives confirmed that a total of 2500 units are sold in batch 1.