Quote Originally Posted by wrinkly View Post
It is confusing
My guess fwiw:

Full time (each half)ends exactly on 45 minutes after kick-off
Injury time starts immediately after full time
The referee tells the 4th official, as near as possible to full time (but not after it) what the extra time is
If an injury starts before full time but continues into injury time then the extra time signalled by the 4th official is only the injury time accrued up to 45 minutes. The injury time after 45 minutes is added on to the end of the game in addition to the extra time signalled - just like any other injury stoppage during the extra time period.

Or the more simple explanation- the ref didn’t know what he was doing