And also keep in mind profitable today with BTC @ $87500 does not mean profitable tomorrow if it drops to $75000. The same thing applies if BTC goes up, you might not be able to make a profit today, but if BTC kits $120000 then you might be well into profit.

Same with power. If you jump from $0.04 kw to $0.05 (yes it's a 25% jump) that could kill profits too.
Even minor fluctuations in cost could hit hard. Add on any other costs such as more cooling needed for the location where you have the miner.

-Dave