Yes, exactly what Patrice said. The 18" measurement should ALWAYS be consistent. The other measurement should be half of whatever the width of the fabric. It has been changing lately - I imagine since the price of fabric is increasing, manufacturers are looking for a way to keep from more increases - thus a narrower fabric width. Just like the FORMER half gallons of ice cream - they're not half gallon size any longer. Lots of packaged food is getting smaller as a way of keeping the price the same.