The chances of a horse placing is dependant on the price of the fav and the price of the horse. Currently a work in progress.
Consider 4th rank.
All in 81200 races win % 10.1% Place % 33.2%. Remembering that 10% wins included so the all in 2nd and 3rd place SR is only 23.1%. With the Fav price from $1 up to $4.50 the place SR goes from 27.5% up to 35.4% while the win SR goes from 6.3% up to 12%. I have only got a quarter way through and only doing it in 50 cent increments.