One reason could be the types of fabrics being used. Flannel rags the best, 100% cotton rags ok, and fleece doesnt rag at all. I've seen some raq quilts that have a mix of fabrics (a different type for each of the 3 layers) and I've seen them all flannell or all 100% cotton. Each mix will give you a different look and feel to the rag. HTH