Okay, from the first article, their blood ketone measurement is even more lenient. They list nonketotic diabetic cats as anything under .9 instead of under .6. Yes, they list non-diabetic cats in a range or 0- .1, but they have anything under .9 as normal for a diabetic cat. Then after that, they list diabetic ketosis as anything from .6 to 6.8. I can only assume this means ECID, and some cats are asymptomatic between .6 and .9, but some cats develop symptoms above .6. In any event, this article from the Journal of Veterinary Diagnostic Investigation seems to agree that anything under .6 on a blood ketone meter is nothing to worry about in a diabetic cat.
The second article is not about what ranges are good, it is about whether the meter I happen to use, Precision Xtra, is accurate when testing cats. They say it is very accurate until one gets to very high levels of ketones. So yay for the Precision Xtra.