The answer to the question is: When the "Additional Assistant Referee" was on the opposite side of the goal to the Assistant referee, he was on the same side of the goal as the Referees patrol path("diagonal"). The powers that be decreed that if the referee followed his patrol path into the box and down to the goal line, the referee would end up right next to the AAR.
So, they moved the AAR to the same side of the goal as the AR where, at least, they would be twenty yards apart ie AAR's position near the goal post to the AR by the corner flag.
Anyway, as Ukraine found out last night, it doesn't matter one hoot which side of the frigging goal he stands, he won't get that crucial decision right!
He was just a social drinker but social every night , he enjoyed a pint or two or three ..