It all depends,these exams are timed so that a person up to the correct standard can complete it within the allotted time,sometimes people are slow because they either don,t fully understand what they are doing or they just don't have the level of skill. I once worked with a young lad who was painfully slow,he also kept checking and rechecking his work.I've known him remove a fused spur 3 times to check he'd wired it correctly,The same lad drove 30 miles back to a job once as he wasn't sure he'd connected something up correctly,despite having repeatedly checked it during the day.I know we all have our off days but when someone is that uncertain they should not be doing the job.