there is probably more time left on the clock and BYU starts the last drive on the 25 not the 16. So the question to go for it or not depends on BYU's ability to get a touchdown on the final drive or make a long field goal. With a shortened field, if you turn it over on downs, I think BYU holds Tenessee to three downs and a field goal and they get the ball back with a 90 seconds with 1 timeout left to go 75 and score vs 54 seconds left and no timeouts to go 60 yards.
I'd take my chances going for it on 4th.