If the conditions for your Winning By or Losing By game plans are satisfied, those will be ones used. The precedence for game plans goes from most the restrictive, first by score, then by time left.
So, if you have a Losing By game plan that becomes active if you're losing by 7 or more with 5 minutes or less remaining, and an Optional gameplan that becomes active if you're losing by 1 or more with 2 minutes or less remaining and you're losing by 10 with 1:45 left, the Losing By plan will be the one in use. If you're losing by 6 with 1:45 left, your Optional game plan will be active. Similarly for when you're winning.