there's never any consistency in it, it's as if now they have board they feel they have to use it all the time.
There were 4 substitutions in the second half at 30 seconds each that is 2 minutes time they should add on. There was one goal during normal time and according to the rules they have to add on one minute so we are already up to 3 minutes and it took about 2 mins and maybe longer to send Barton off. That means the ref is saying if there were no subs and no sending off etc the game would have ended at 90 mins
We all know we still would see the standard 3 mins they always put up.
A lot of the time when goals are scored during injury time they don't add on the extra one minute that is in the rules although this time I think they did.