No Fixed Abode It's pretty frustrating when the officials indicate there's 4 minutes added on time then perhaps one teams will make a sub to 'waste' time - the ref should add on some extra time but many fail to do so. Or sometimes when a goal is scored.
They seem to add the extra 30secs on for an injury time sub, but they certainly shouldn't for a goal. Unless it takes an undue amount of time to restart play, a referee should never add on time when the ball goes out of play. I've seen plenty of refs do this though, which is clearly not right. I'm sure during the infamous Reading/ Arsenal 5-7, the ref added on time when Arsenal made it 3-4, despite having not done so for the previous 6.