Another reason why the COT rule, as currently interpreted, is ridiculous.
Another thing to keep in mind is that sometimes you can really wake a horse up by changing things up on it.
Take a horse that usually leaves hard & jag him off the gate to save him up for one late shot at them...or conversely you can take a horse that usually jags off and looks for cover, stoke him up in the prelim. and leave hard, looking for the front.
Doing that sort of thing with some horses, especially older ones that have had a few starts and are in a bit of a rut, can often bring good results.