William Hill NRL Winners Bonus Promo

Place minimum $30 on any team to win the NRL premiership and get a $5 bonus bet for every game they win during the season (excludes SA residents)

Am I missing something here? Roosters won 18 games last year, so off $30 you would get $90 in bonus bets and then the team may even win the big one for a juicy payout too.