Normally, the total additional payment shows up as a single amount, called an "add collect". It comes at the end of the "linear fare calculation", the long list of routings, fares, and fare basis codes just following the form of payment in the middle of the passenger receipt. The add collect is abbreviated A/C. In your case, it sounds as if the agent made an error and collected $44 twice instead of $44 once and $100 once.