Since moving to NC, I have been obsessed by this use of "level." Not only is there no readily available explanation, it's almost impossible to make one up that is even remotely plausible. I can only imagine (lacking anything like, say, facts) that "level" is actually another word altogether, much as asparagus is, in some places, called "sparrow grass." But if it is true, then what is that other word, or words? Or what if, as in Colorado Springs, there were the intention to create an impression contrary to fact, for real-estate reasons?

But enough conjecture. Time to get sleuthing.