Yeah, that’s one of those goofy things one sees in these burnt city press releases. A 10 cm ruler that is a half a millimeter too long means it wasn’t 10 cm long in the first place. :’)
Are they saying that there was some unit of measure that was about 10 centimeters that these people used, and they found a ruler that measured in those units? I was very confused by this part. But I enjoyed the article.