Software is one answer and it is not the first one. If the number above is uncomfortable, these three cost nothing and most shops have not done them.
Print a rate card and put it on the wall. A large part of the time a bill takes is deciding what to charge while the customer watches. A written rate ends that conversation before it starts, and it also stops the quiet discounting that happens when a price is decided in front of somebody. The rate card guide works through how to set one.
Number every order, and write the number on the customer’s slip. Most of the searching in a tailoring shop is not for measurements at all — it is for which order this person is asking about. A number on both halves turns that into one question.
Write the date beside every measurement. Undated numbers get re-taken because nobody trusts them, and that re-measuring is invisible time. A date makes an old record either usable or obviously not, and both are better than a guess. The technique is in how to take measurements for stitching.
Do those three first. Then run this calculator again with your new bill time, and see whether what is left is worth paying to fix.