Im in the belief it is to do with the fact the LED 5 does not have a negative source running to it.
See the link below:
"Sony must have some ideas for putting a led there but never did.
the spot still has a positive but no negative so we have to add a negative to the led, the led in this tutorial is always on because i haven't found a negative source that turns one when power goes through it. if anyone can find one that would be great."
Hope this helps.