I’m actually at 0.8 right now, but it’s temporary. I detatched and fertilized. I read that the process of detatching accelerated growth, so I pumped up the coefficient for a bit. It seems to be working as the areas that were previously brown are filling in nicely. In another week or so I’m going to be dialing the crop coefficent back down gradually, until I get back to around 0.65 if I can push it that low. I found this where @Franz also mentions 65%. I know they recently increased the Cool Season default to 0.8.
By the way @AzJazz, if you haven’t dethatched in a long time that might be part of the problem with the lawn, assuming we confirm that your settings are reasonable.