As a follow-up to my Salami in Oil posting, here's another story posted to the Microsoft Excel Developers List Excel-L, by Lex Marshall. May I add that I'm a whizz at programming spreadsheets and other things with numbers that stand for money in: I'd be happy to oblige, should any of you feel like making me an offer that would keep my bar well stocked.
Back in the 1960's when most smaller IBM customers rented IBM Unit Record Equipment (punch cards) the rental included programming support (but, of course, programming meant "hard wiring" control panels).
I was a young IBM trainee who had a reputation for being able to program those suckers. Consequently, I was directed to do an invoicing control panel for a pharmaceutical wholesaler. The owner asked if we could round up the sales tax calculation on every line item. Since the sales tax rates were all fractional percentages such as 12.5% and so on, it was likely that almost every line item would have an amount to be rounded up.
I calculated that he would gain about $250 per month over what he would have to pay the Sales Tax people. He said that he knew that (which is why he wanted it done that way) and that it would help to keep the bar in the boardroom well stocked.