When you're down 24-20 and have 4th down and 2 deep in their zone with 3:45 to go.

Why don't you take the guaranteed fg?

Then you're down 24-23. If you stop them bingo you just need a fg. If you don't stop them and use your timeouts, let them run in for the TD. Then you're down by 8 and still have a shot with say 2:30ish left on the clock.