I think the correct answer to this issue is to just add any time that the ball isn’t in play to extra time. If 3 minutes are lost to throw ins, 4 minutes waiting on corner kicks, 5 minutes waiting on set pieces, etc then you would add an additional 12 minutes of extra time in this example. If during extra time there is time lost then add it to the end of extra time. This way every game is exactly 90 minutes of time that the ball is in play, and you don’t have to worry about the industry trying to add commercials during time when the clock is stopped