A lot is being said of the substitutions last night and whether RK made a critical error.
A slightly alternative question could be, where on earth did the fourth official get "a minimum of four extra minutes" from ??
Neither side needed any medical attention second half and at 15 seconds per substitution, that's about 1 minute... even though they brought two on at once... allow maybe one minute or 90 seconds for a bit of time-wasting and at most it was three minutes.
I honestly fail to see where the four minutes came from and how they can be justified.
Think it's 30 seconds added on for each substitution mate, refs also will add time on after they book a player as well.