That will happen gradually, Stores will then make $2,700,000 a month at a conservative starting rate of $6000 a day, with a difference in sales:cost of stores of +$2,400,000 a month, 66% gross profit, thats $1,584,000 extra in gross profit per month.
15 stores x 5100/mo rent = $76,500 + payroll, electricity, food, lunch, utility, travel, carpentry, repair, security, etc = ~$300K
15 stores x 6000/day x 30 days =$2,700,000