andy here, i working at UOB bank one.. about this question, You earning 2% of smart cash at bhp petrol station, and another 5% more cash back will be deducted in your bank statement, not on the receipt one. and the smart cash, after u collect many smart cash, next time you go to bhp petrol station, you can ask the staff to use the smart cash to pump petrol .it can be just use like money.