I feel if your going to sit a man on the bench and not start him until the 74th minute or later, then that person should be a player with the mindset and free licence to go out there and try things that the rest of the team have failed to do. eg if the team is down by 20, send the guy out there to have a go and score.
If your winning by a country mile, throw him out there with the view of attacking the oppositions weakness and put them out of their misery, that type of player Perham could be, definately not a forward, to use a forward at that stage of the match is just too late and stupid(unless you wanna give one of your guys a break)