all profitability numbers are bogus anyway with btc being $380 one day and $295 the next.
the only play here is for halving-associated btc expected jump.
So, you accumulate coins like there is no tomorrow, then sell some.
If no jump, then profits would be marginal, if any.
The problem is that you spend 1600 using BTC now with the risk of having less BTC when price doubles...
The only play, IHMO, is hoping that difficulty slows down to 1 or 2% max per retarget, otherwise the risk of ending up with less BTC one year from now seems real.
Did ROI calculators a year ago predict that the S5's would still be worth what they are today? They haven't really depreciated much at all in fairness. For quite a few generations now skeptics have doubted ROI, assuming that difficulty would drive hardware obsolescence. And yet, those who have bought hardware for the past 12 months have done considerably better than those who have bought coin. We have reached the point where you can factor equity into the purchase price of miners, unlike early generations of ASICs, and that is something that calculators do not include.
Don't forget that for a good half of 2015 difficulty moved very little, now it seems we're back at 4-5% increase each retarget.
Anyway, if, as it seems, there is a lower electricity cost available now.. well, let's redo again all our calculations and predictions and see what they give.
spiccioli