so 885-670 = 215/28.50 = at 7 ½ months  which is much better then  480/28.50 = 16.84 months.

The Trump tax  hurts bitmain  bigtime.

I would argue  that at 7 cent power buying any gear is a tough choice for a USA guy.

If you are a 4 cent guy:

4 x 750 = a 30 cent power savings  new gear
old gear earns  24 more   so net is 6 dollars    

So no 4 cent power guy wants  the new gear  it is only 6 dollars better each month.

This means  only a handful of buyers want the new gear.  6 cent 7 cent  8 cent power guys it makes sense.

maybe 9 cents  and anyone over 9 cents should not mine much right now.

2,3,4,5 cent  should  think old s9i
6,7,8,9 cent  maybe  new gear is better.
10 cent and up no gear.

So a lot of people don't want the gear.