So at current difficulty you would get 256 dollars per month minus 2,925 per day is 168,25 dollars per month of income.
That's an ROI of about 10 months if the difficulty doesn't rise.
According my experience, I am pessimistic if can RoI 10 months, based on the experience of the S7 reality if different. First time promotion of S7, the estimated RoI is 8 months, but in reality more than 15 months.