That's how I read it at first, second, third...I finally saw it. They had to know when they made that sign.
Someone tried this on me as well when I worked at Dunkin’ Donuts back in high school. He went around and around a few times and I kept giving him the correct change back. He tried arguing but I just looked at him and told him that I was good with math and I know he had gotten the correct change. He just smiled and shook my head. Guess he appreciated the battle even if it didn’t end in his favor. And here I am an accountant 15 years later so I guess things end up how they should.
No problem! Somebody pour me a Makers Mark on ice!