It seems deliberately confusing to me since there is no fundamental difference between voting now and voting on the day of the deadline, but the way it’s discussed and referred to seems to imply that the correct day to vote would be waiting until the last minute instead of voting just getting it out of the way weeks ahead of time.
Both answers are correct. 20 years divides into 5 sets of 4, but that’ would only be 5 elections if you started counting on an election year.