I hope tiemco will stop by to explain some of the characterstics to look for in turf types and cultivars. I can tell you that grasses are labeled by the pound, so a 50 pound bag of a mix labeled 10% KBG would mean 5 pounds of KBG is in the bag. However, 1 pound of KBG can contain over 1 million seeds, wheres a pound of fescue will contain only a couple hundred thousands seeds, so, you may be actually getting a 50/50 mix of fescure and KBG in that bag.

Here's a link that I have found usefull for ID of cool season grasses.

Here is a link that might be useful: Cool Season turf ID