It's not about accuracy as you perceive. It is about how valid human witnessing is, say, in a human court. If a witness A says that the crime occurred at 10:31 am sharp on Thursday because he was by then timing a clock. While another witness B says that it's 10:45 am on Wednesday because usually by that time and day he's in a location near the crime scene.
The both wrote separately about their witnessing. So are they considered valid in the court. What's behind the scene is that B is usually near the crime scene on every Wednesday, but in that particular week during the crime and for a reason he forgot, he went there on Thursday instead. Will a judge validate his witnessing for the crime or invalid his witnessing at all?