The way I see it, you have to use (enable) one of the "optional" settings.  You should be able to import your playbook, input the point(s) differential, input the time.  Not 100% sure with 3.0, but with 2.0 the time meant for each half.

The only thing you can change on those is the time they kick in and the game plan used.  I suppose the thinking is late in the game / half, you will probably want to make SOME adjustment based on if you are winning, losing, or tied.
 

You can use the optional game plans to set more granular values like if you need a TD instead of a FG, or a two-score game, etc.