16 is just the average closing price (VWAP), morning opening price when you want to square of your position can be anything, from 0.05 to infinity! so yes, if your direction is right you’ll earn, if not you’ll lose. There is no arbitrage between LTP and VWAP closing. Even though VWAP price was 16, you need to find a counter party who’ll buy it from you for 16, VWAP is used only for MTM settlement and does not reflect current market price.
if you trade to earn 30 paise, you’ll pay more in commissions, and if you want to scale this strategy, then your actually risking more money, if the market moves against you. There’s no free money in the market. If you want to earn, you’ve to take risk and bet on your assumptions.