All Brownlow markets are subject to Dead Heat rules. In the event of a tie or a draw for a position, the dividend will be calculated by the odds divided by the amount of selections tied for the position.
For example, if I had a $10 bet on for Matt Rowell to finish top 5 at the odds of $1.50, my initial return will be $15. However, if Matt Rowell & Caleb Serong tied for 5th (their finishing positions were 5th & 6th), the total payout is divided by 2.
$15 divided by 2 = $7.50 which is what your return will be.