1. Time to complete the task is a terrible metric for white-collar, knowledge work. There are myriad factors to explain the time discrepancies, especially since there wasn't first-hand observation. If this was a job for building a widget on a factory line, then time might be a reasonable metric.
2. Using time alone as a selection criteria borders on discrimination given that some users might have sight or other physical disabilities that require longer to complete the task.
3. Do you really want to work for someone that has that kind of attitude? Oh, you're worthless because you took a few hours longer than John over there. We're not even going to consider your other talents, abilities, capabilities, or creativity that you bring to the table.