Got a picture of this receipt from a friend of mine who dined at a local chain restaurant the other day. He noticed that the percentages listed for the tip didn't quite meet the totals shown.

It is awfully nice to have this close at hand for easy reference and as stated these are provided for your convenience. However they are wrong! By my calculations the percentages shown are 20%, 24% and 27%!

I always figure my own tips but how about those that are mathematically challenged and are going by the suggestions posted here? I am led to believe that these machines and percentages are set by the establishment and wonder if this is on  purpose or just an misstep in accounting.

Have you worked for a company that manipulates tips this way to the advantage of the server? Is this just an honest mistake? let us know.