What is the difference in returns between dividend pay and reinvestment option

In one of reply to query you have mentioned that while switching the fund from dividend payout option to growth option, you need to keep two things in mind - 1) Exit load may be applicable as you are switching before 12 months. Please check the exit load percentage and the time period on the statement, 2) If you are making any profit on the switch, then it will be treated as short term capital gains and tax @15% shall be payable when you are filing your income tax returns. What is the implications if I want to change from dividend payout option to dividend reinvest?