Why have u rated grade 5 higher than grade 4??? It goes the other way. Maiden then to grade 5, 4, 3, 2, 1. So a grade 4 is for dogs that have won their grade 5 on that track. I think if you lose 2 races in one grade u can drop back a grade also. Also a dogs grade at each track is independent. So a grade 4 dog at Wenti Park could still be a grade 5 dog at Nowra, The Meadows etc.

Also surely the mixed grade 4/5 rating should be inbetween the grade 4 and grade 5 rating. It is slightly stronger than the grade 5 and slightly weaker than a grade 4.