As an American, I have always written both the tip and the total on the slip. Until this moment, I have never actually considered only writing one or the other

As an American, I have always written both the tip and the total on the slip. Until this moment, I have never actually considered only writing one or the other. I probably will continue to write both as I'm a little paranoid about people making changes to the values before they get put into the machine, and having to change 2 lines is harder than 1.