....
100ROI in next 85days assuming the difficulty doesn't raise!
Difficulty alone is irrelevant. Most important in this aspect (ROI) is ratio diff/price of BTC. If this will stay at similiar levels then ROI in 85 days. Future will tell how it will be....
It will be the same difficulty or less for the next 15 days :
-1.51% in 0 days Next difficulty
But it is likely to raise within 85days.