The other thing for Syd and Melb may be the class rises are greater ,simply meaning if you cant win one grade down your chances are greatly reduced be cause you really do meet a better horse. I have never seen a study on horse’s wins or placings going up or down in class let alone on diffrent tracks have always worked on the assumption that a horse in the same or down in class would be a better chance given all being equal over time but have no idea how this affects price.