[a4caster]

Sometimes used example is whatever helps them/hurts them the most. This is not a perfect example, as there are times where the opposite happens. But for the most part, it works. CIP; running play, A clips, runner goes 30 yds. You wouldn't subtract it from the end of the run; hit them where it hurts the most - the spot of the foul. The only time this doesn't work is on a pass play where B fouls (hold, BIB) and the pass is made over 10 yds. PS is the LOS, so either take the penalty or decline, it's still usually a 1st down. Only exception is if it was down and +10 yds. Then, you get to replay the down. So there are not perfect templates, but game knowledge comes into play alot. Give it time; it took me a long time to get the hang of it as well. Once you do, it all clicks!