In accounting, no, while preparing input to the accounting in the form of generating invoices, I've lost count (sorry) of the number of times I've seen people doing tax calculations etc. on unit prices and then multiplying by number of units ordered, and then further compounding potential issues by adding up these numbers from multiple invoice lines. None of which is usually the right thing to do, all of which you often "get away with" without causing sufficient discrepancies, and so which people often fail to catch in testing. Until you suddenly don't.