With up to four cars on course and a single start/finish beam, finishes are recorded to the oldest car in the queue. That is right almost every time, and wrong when a car is passed, pulls off, or is waved through.
The fix is a reassignment, not a recalculation. From the live feed you can reassign a mis-matched finish to the correct slot, record a DNF for a car that did not complete, or DQ a time that should not count - a pass that invalidated the field, or a missed beam.
Runs can also be added, edited or deleted by hand, which covers backup timing and protests.
The important part is that the corrections happen in the moment, from the screen you are already looking at, rather than in a scoring pass at the end of the day.