Number of vils on berries

Hey I am a new player trying to learn. How many vils should be gathering berries on the beginning of the game? Most sources I've read advise to have 4 on berries, but in interactive build order for FC + knights it tells me to have 5.

Does this 1 vil make a big difference? When should I have 4 and when 5 vils on berries? This is probably a stupid question but I just want to understand and not to blindly follow build order.