Horse won but by DH
1. One point back to win bet gives: half the (odds-1) profit???
2. Lay to win bet for one point gives: 0.5pts minus (half the (odds-1)) profit???
When a horse wins in a dead heat you calculate wins/losses by assuming half the bet won and half lost so it's the stake you divide by 2 (3 if triple heat etc) not the odds.