Watching lots of footy games (as I have to in this family) I wondered why they don't adopt the RL method of "stopping the clock" for injuries etc.
Not only does it sort out the added minutes at the end but add to the excitement as the fans count down.
In effect they do do this. The ref stops his clock for any stoppages or time wasting he then tells the 4th offical how much time was wasted, this is then called stoppage time. The 4th offical and the announcer then inform the fans just how long stoppage time is 1, 2, 3 mins etc.
The fans can then just look at the stadium clock (most must be digital by now) and see how long is left of the extra 1,2,3 mins etc.