If you go to the Kaufman web site you will see there is more than one fabric line with the Kona name inculded. I think I recall seeing about 6 or 7 . So just seeing the name Kona does not give the apples to apples comparison. Look at all of the info on the end of the bolt.
Same is true for muslin , as far as looking at more than the name on the end of the bolt.... one manufacture has at least 8-10 different grades or specifications ..again look at all of the info on the end of the bolt. I had a freind tell me about this great bargain on muslin ... she bought lots of it. It had the same manufacture as the one I typically purchase. She focused only on the name... Well what she bought was this particular companies low end muslin... low thread count , lots of shrinkage , and more wrinkles than a prune. The muslin I purchased was higher end , high thread count, minimal shrinkage, and ironed just as nice as any LQS fabric.