When S7 release it has more than 12 months BEP (include tax)
Actually, it's BEP per your stated method of calculation of the S7 at release was a little over 8 months, NOT 1 year.
I came up with an estimate that it would be 4 BTC before release based on a 250 day BEP, but that was assuming 2 hash boards 2 strings and therefore a little less than half the TH at a little less than half the power at a BTC price when I made the estimate of a hair more than the release date - given the actual figures, it should have been released at more like 8.5 BTC for a 250 day BEP. (Bitmain appears to assume appx. 10 cent / KWH on their version of your BEP calculation).
I have ZERO CLUE where you are comming up with that "1 year" figure for it, that's not even close given your base assumptions on the calculation unless your electric rate used is quite a bit HIGHER than 10 cents / KWH.
If you calculated with raw number its around $375 usd per THS and its expensive, for start up. But its not fair so I give you the detail, heres my calc :
Setup :
S7 = 1823
PSU = 155
Shipping = 72.45
SUB TOTAL = 2050.45
TAX 25% = 512.6125
TOTAL = 2563.0625 usd
Tax should be 20% but its bullshit since theres smalls charges for whatever
Cost :
Total kwh a month = 1.210 kw x 720h = 871.2
With elec prices 0.1 per kwh = 87.12 usd a month
Income :
Around 300usd (296 last night and 304.2 this morning)
Nett income = 300-87.12 = let say 223 usd a month
So BEP around 2563 divide by 223 usd = 11.49 month
Even all this "good" number is true IF :
*You plug it right now, not next month
*Without diff raising
(right now estimated diff 7%++ and maybe more than 50% when I get the S7 since they sold to local faster)I love bitmain, I have good quality services and products since the legend antminer S1. But this price is too high for home miner. But then again, nobody can compete bitmain right now or even in February 2016 too.